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Practical problems

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CONTENTS

ITEM TYPE NUMBER
Day-to-day problems Workout 34 slides
Practical problems Library 18 questions
Once you have registered, you can work through the slides one by one. The workout comprises a series of sides that guide you systematically through the topic concept by concept, skill by skill. The slides may be used with or without the support of a tutor. The methodology is based on problem-solving that advances in logical succession by concept and difficulty. The student is presented with a problem or series of questions, and the next slide presents the fully-worked solution. To use the material you must sign-in or create an account. blacksacademy.net comprises a complete course in mathematics with resources that are comprehensive.

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SAMPLE FROM THE WORKOUT

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SLIDE 1 - QUESTION 1

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SLIDE 2 - SOLUTION

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SAMPLE FROM THE LIBRARY

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QUESTION [difficulty 0.1]

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SOLUTION

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DEPENDENCIES

200: Long division
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204: Practical problems
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206: Order and type of numbers

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CONCEPTS

ITEM
LEV.
Paying by instalments 424.5
Loan 424.5
Deposit 424.5
Sales, turnover 426.9
Down-payment 427.1

RAW CONTENT OF THE WORKOUT

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SLIDE 1 Four colleagues go on a business trip together. Their costs are £1,580 for four return plane tickets, £740 to rent an apartment, £320 to hire a car. What is the cost per colleague for the journey? SLIDE 2 Four colleagues go on a business trip together. Their costs are £1,580 for four return plane tickets, £740 to rent an apartment, £320 to hire a car. What is the cost per colleague for the journey? The total cost is £2640. When this is divided between four people the cost per person is £660. SLIDE 1B Four colleagues go on a business trip together. Their costs are $1,580 for four return plane tickets, $740 to rent an apartment, $320 to hire a car. What is the cost per colleague for the journey? SLIDE 2B Four colleagues go on a business trip together. Their costs are $1,580 for four return plane tickets, $740 to rent an apartment, $320 to hire a car. What is the cost per colleague for the journey? The total cost is $2640. When this is divided between four people the cost per person is $660. ? ? SLIDE 3 The cost of 1 tin of jam is £3.50. What is the cost of 8 tins? SLIDE 4 The cost of 1 tin of jam is £3.50. What is the cost of 8 tins? Solution Answer: £28 SLIDE 3 The cost of 1 tin of jam is $3.50. What is the cost of 8 tins? SLIDE 4 The cost of 1 tin of jam is $3.50. What is the cost of 8 tins? Solution Answer: $28 SLIDE 5 Paying by instalments A typical way in which people buy a good is to pay a fixed sum over a period. Each fixed payment is called an instalment. Often the purchaser has to make a first down payment, also called a deposit. Buying a good like this is a way to taking out a loan. A loan company lends the purchaser the money, and the total paid is greater than the original price. The loan company makes a profit by charging interest. Question The total cost of a family holiday was £4,200 plus sales tax of £840. The family paid a deposit of £1,200. The rest of the money was paid in 6 equal monthly instalments. Work out the amount of each monthly payment. SLIDE 6 The total cost of a family holiday was 4,200 plus sales tax of £840. The family paid a deposit of £1,200. The rest of the money was paid in 6 equal monthly instalments. Work out the amount of each monthly payment. Solution Answer: £640 Notes for tutors Here we see a theme of language across the curriculum. A practical problem arises in the world, and involves new ideas such as loan, profit, deposit and instalment. The student not only needs to understand the mathematical solution but needs to understand the practical context. That goes together with an expansion of vocabulary sufficient to describe the real-life problem. Paying by instalments A typical way in which people buy a good is to pay a fixed sum over a period. Each fixed payment is called an instalment. Often the purchaser has to make a first down payment, also called a deposit. Buying a good like this is a way to taking out a loan. A loan company lends the purchaser the money, and the total paid is greater than the original price. The loan company makes a profit by charging interest. SLIDE 5b Paying by instalments A typical way in which people buy a good is to pay a fixed sum over a period. Each fixed payment is called an instalment. Often the purchaser has to make a first down payment, also called a deposit. Buying a good like this is a way to taking out a loan. A loan company lends the purchaser the money, and the total paid is greater than the original price. The loan company makes a profit by charging interest. Question The total cost of a family holiday was $4,200 plus sales tax of $840. The family paid a deposit of $1,200. The rest of the money was paid in 6 equal monthly instalments. Work out the amount of each monthly payment. SLIDE 6b The total cost of a family holiday was $4,200 plus sales tax of $840. The family paid a deposit of $1,200. The rest of the money was paid in 6 equal monthly instalments. Work out the amount of each monthly payment. Solution Answer: $640 SLIDE 7 Mr. Read wishes to travel to Alaska with his wife and daughter aged 10. They have $1600 dollars to spend. The table shows prices of flights on selected days. Outward flight Return flight Date Adult ticket ($) Date Adult ticket ($) 3 June 300 15 June 310 4 June 320 16 June 400 5 June 280 17 June 350 6 June 280 18 June 310 Flights for children below 16 are half of the price of the adult ticket. ? Can Mr. Read afford to travel out on 3 June and return on 17 June? ? What is the option Mr. Read can afford that gives him the most time in Alaska? SLIDE 8 Mr. Read wishes to travel to Alaska with his wife and daughter aged 10. They have $1600 dollars to spend. The table shows prices of flights on selected days. Outward flight Return flight Date Adult ticket ($) Date Adult ticket ($) 3 June 300 15 June 310 4 June 320 16 June 400 5 June 280 17 June 350 6 June 280 18 June 310 Flights for children below 16 are half of the price of the adult ticket. Solution ? Can Mr. Read afford to travel out on 3 June and return on 17 June? 3 June: 17 June: too expensive ? What is the option Mr. Read can afford that gives him the most time in Alaska? 5 June: 18 June: 3 June to 18 June costs $1525 and is also affordable, but the 5 June to 18 June option is the best. SLIDE 9 A shop sells mayonnaise in three different sizes. 200 ml costs £4. 300 ml costs £5.40 400 ml costs £7.60 Which size is best value for money? SLIDE 10 A shop sells mayonnaise in three different sizes. 200 ml costs £4. 300 ml costs £5.40 400 ml costs £7.60 Which size is best value for money? Solution Cost per 100 ml. Answer: 300 ml for £5.40 SLIDE 9 B A shop sells mayonnaise in three different sizes. 8 fl. oz. costs $4. 12 fl. oz. costs $5.40 16 fl. oz. costs $7.60 Which size is best value for money? SLIDE 10 B A shop sells mayonnaise in three different sizes. 8 fl. oz. costs $4. 12 fl. oz. costs $5.40 16 fl. oz. costs $7.60 Which size is best value for money? Solution Cost per fluid once. Answer: 12 fl. oz. for $5.40 SLIDE 11 Oil is sold in two sizes. A 1.6 litre bottle normally costs £10. A 6.4 litre bottle costs £35. A shop is offering a reduction of one tenth on a purchase of two or more 1.6 litre bottles. Is it cheaper to buy the 6.4 litre bottle, or four 1.6 litre bottles? SLIDE 12 Oil is sold in two sizes. A 1.6 litre bottle normally costs £10. A 6.4 litre bottle costs £35. A shop is offering a reduction of one tenth on a purchase of two or more 1.6 litre bottles. Is it cheaper to buy the 6.4 litre bottle, or four 1.6 litre bottles? Solution Reduction of one tenth is £4 But it is still cheaper to buy the 6.4 litre bottle at £35. SLIDE 11B Oil is sold in two sizes. A 1.6 pint bottle normally costs $10. A 6.4 pint bottle costs $35. A shop is offering a reduction of one tenth on a purchase of two or more 1.6 pint bottles. Is it cheaper to buy the 6.4 pint bottle, or four 1.6 pint bottles? SLIDE 12B Oil is sold in two sizes. A 1.6 pint bottle normally costs $10. A 6.4 pint bottle costs $35. A shop is offering a reduction of one tenth on a purchase of two or more 1.6 pint bottles. Is it cheaper to buy the 6.4 pint bottle, or four 1.6 pint bottles? Solution Reduction of one tenth is $4 But it is still cheaper to buy the 6.4 pint bottle at £35. SLIDE 13 Two dealers make an offer on their used cars. Dealer A. Sale price. 1/5 off the price of any car up to £2,200. Dealer B. Sale price. 1/4 off the price of any car normally priced over £1,800. A special offer is made by both dealers: If the sale price is over £1,800, then take another tenth off. Is a car normally priced at £2000 at Dealer A cheaper than a car normally priced at £2,500 at Dealer B? SLIDE 14 Two dealers make an offer on their used cars. Dealer A. Sale price. 1/5 off the price of any car up to £2,200. Dealer B. Sale price. 1/4 off the price of any car normally priced over £1,800. A special offer is made by both dealers: If the sale price is over £1,800, then take another tenth off. Is a car normally priced at £2000 at Dealer A cheaper than a car normally priced at £2,500 at Dealer B? Solution Dealer A: 1/5 is £400. No further reduction Dealer B: 1/4 of £2500 is £625 A further tenth is £187.5 Dealer A is cheaper. SLIDE 13B Two dealers make an offer on their used cars. Dealer A. Sale price. 1/5 off the price of any car up to $2,200. Dealer B. Sale price. 1/4 off the price of any car normally priced over $1,800. A special offer is made by both dealers: If the sale price is over $1,800, then take another tenth off. Is a car normally priced at $2000 at Dealer A cheaper than a car normally priced at $2,500 at Dealer B? SLIDE 14B Two dealers make an offer on their used cars. Dealer A. Sale price. 1/5 off the price of any car up to $2,200. Dealer B. Sale price. 1/4 off the price of any car normally priced over $1,800. A special offer is made by both dealers: If the sale price is over $1,800, then take another tenth off. Is a car normally priced at $2000 at Dealer A cheaper than a car normally priced at $2,500 at Dealer B? Solution Dealer A: 1/5 is $400. No further reduction Dealer B: 1/4 of $2500 is $625 A further tenth is $187.5 Dealer A is cheaper. SLIDE 15 A metal frame is made from wire. The height of the frame is 1 metre and the width 3 metres. The weight of the metal is 4 kg per metre. What is the weight in kg of the metal in the frame? SLIDE 16 A metal frame is made from wire. The height of the frame is 1 metre and the width 3 metres. The weight of the metal is 4 kg per metre. What is the weight in kg of the metal in the frame? Solution Total length metres Total weight kg SLIDE 15B A metal frame is made from wire. The height of the frame is 1 yard and the width 3 yards. The weight of the metal is 4 lb per metre. What is the weight in lb of the metal in the frame? SLIDE 16B A metal frame is made from wire. The height of the frame is 1 metre and the width 3 metres. The weight of the metal is 4 kg per metre. What is the weight in kg of the metal in the frame? Solution Total length yards Total weight lb SLIDE 17 A farmer wishes to build a fence around a field, which has a diameter of 1400 m. The length of the semicircular part is 2200 m. It costs £50 for each 100 m of fence and will take 3 days to build. The cost of each day of work is £180 per day. What is the total cost of building the fence? SLIDE 18 A farmer wishes to build a fence around a field, which has a diameter of 1400 m. The length of the semicircular part is 2200 m. It costs £50 for each 100 m of fence and will take 3 days to build. The cost of each day of work is £180 per day. What is the total cost of building the fence? Solution Total length: Cost of labour: Total cost: SLIDE 17B A farmer wishes to build a fence around a field, which has a diameter of 1400 yd. The length of the semicircular part is 2200 yd. It costs $50 for each 100 yd of fence and will take 3 days to build. The cost of each day of work is $180 per day. What is the total cost of building the fence? SLIDE 18B Solution Total length: SLIDE 19 A gardener wishes to put a plastic strip around the edge of a flower bed, which is a circle with circumference 22 m. The plastic strip is sold in rolls of 6 m. How many rolls of plastic strip will the gardener need to buy? SLIDE 20 A gardener wishes to put a plastic strip around the edge of a flower bed, which is a circle with circumference 22 m. The plastic strip is sold in rolls of 6 m. How many rolls of plastic strip will the gardener need to buy? Solution 4 rolls needed, with 2 m left over. SLIDE 19B A gardener wishes to put a plastic strip around the edge of a flower bed, which is a circle with circumference 22 yd. The plastic strip is sold in rolls of 6 yd. How many rolls of plastic strip will the gardener need to buy? SLIDE 20B A gardener wishes to put a plastic strip around the edge of a flower bed, which is a circle with circumference 22 yd. The plastic strip is sold in rolls of 6 yd. How many rolls of plastic strip will the gardener need to buy? Solution 4 rolls needed, with 2 yd left over. SLIDE 21 The table gives the rates of pay of a shop assistant. Day Rate of pay Monday to Friday £9.60 per hour Weekend £12.20 per hour The assistant worked 35 hours in a week, of which 12 were at the weekend. Her rent is £150 dollars a week. How much did she have at the end of the week after she had paid the rent? SLIDE 22 The table gives the rates of pay of a shop assistant. Day Rate of pay Monday to Friday £9.60 per hour Weekend £12.20 per hour The assistant worked 35 hours in a week, of which 12 were at the weekend. Her rent is £150 dollars a week. How much did she have at the end of the week after she had paid the rent? Solution hours at the basic rate Monday to Friday Weekend Total pay Net after rent SLIDE 21B The table gives the rates of pay of a shop assistant. Day Rate of pay Monday to Friday $9.60 per hour Weekend $12.20 per hour The assistant worked 35 hours in a week, of which 12 were at the weekend. Her rent is $150 dollars a week. How much did she have at the end of the week after she had paid the rent? SLIDE 22B Solution hours at the basic rate Monday to Friday Weekend Total pay Net after rent SLIDE 23 What is the total cost of six pens for 80p, fifteen pencils at 40p, four rulers at £1.25 and eight exercise books at £2.15? SLIDE 24 What is the total cost of six pens for 80p, fifteen pencils at 40p, four rulers at £1.25 and eight exercise books at £2.15? Solution Total cost: SLIDE 23B What is the total cost of six pens for 80¢, fifteen pencils at 40¢, four rulers at $1.25 and eight exercise books at $2.15? SLIDE 24B What is the total cost of six pens for 80¢, fifteen pencils at 40¢, four rulers at $1.25 and eight exercise books at $2.15? Solution Total cost: SLIDE 25 A young girl decides to make money by selling sweets to her friends. She buys 10 kg of sweets for £24. She buys sufficient little boxes for £2. She divides the sweets into 250g amounts and puts each of these amounts into the boxes. She sells each box for 95p. Assuming she has no boxes left over, what profit did she make? Hint 250g is ¼ of a kilo, so there are 4 times 250g in 1 kg. SLIDE 26 A young girl decides to make money by selling sweets to her friends. She buys 10 kg of sweets for £24. She buys sufficient little boxes for £2. She divides the sweets into 250g amounts and puts each of these amounts into the boxes. She sells each box for 95p. Assuming she has no boxes left over, what profit did she make? Hint 250g is ¼ of a kilo, so there are 4 times 250g in 1 kg. Solution Costs Number of sales Revenue Profit SLIDE 25B A young girl decides to make money by selling sweets to her friends. She buys 10 lb of sweets for $24. She buys sufficient little boxes for $2. She divides the sweets into 4oz amounts and puts each of these amounts into the boxes. She sells each box for 95¢. Assuming she has no boxes left over, what profit did she make? Hint 4 oz is ¼ of a pound, so there are 4 times 4 oz in 1 lb. SLIDE 26B Solution Costs Number of sales Revenue Profit SLIDE 27 The same young girl decides to expand her business. She buys 1000 kg of sweets for £1,900. She buys sufficient boxes for £60. She pays a boy to pack the boxes containing 250g of sweets, giving him a wage of £8 per hour. She sells each box for 95p. He packs 50 boxes per hour. What is her profit? 250g is ¼ of a kilo, so there are 4 times 250g in 1 kg. SLIDE 28 The same young girl decides to expand her business. She buys 1000 kg of sweets for £1,900. She buys sufficient boxes for £60. She pays a boy to pack the boxes containing 250g of sweets, giving him a wage of £8 per hour. She sells each box for 95p. He packs 50 boxes per hour. What is her profit? 250g is ¼ of a kilo, so there are 4 times 250g in 1 kg. Solution Number of sales Hours worked Wage costs Costs Revenue Profit SLIDE 27B The same young girl decides to expand her business. She buys 1000 lb of sweets for $1,900. She buys sufficient boxes for $60. She pays a boy to pack the boxes containing 4 oz of sweets, giving him a wage of $8 per hour. She sells each box for 95¢. He packs 50 boxes per hour. What is her profit? SLIDE 28B Solution Number of sales Hours worked Wage costs Costs Revenue Profit SLIDE 29 The same young girl decides to expand her business a second time. She buys 10,000 kg of sweets for £15,000. She buys sufficient boxes for £600. She pays several boys to pack the boxes each containing 250g of sweets, giving them a wage of £8 per hour. They pack the boxes at 50 per hour. She sells the sweets for 95p per box. The government gets wind of her business and imposes a social security payment of £1 per hour worked by the boys; then a 4/10 tax on her profits before social security is taken off, and a fine of £20,000 for not declaring her turnover. Calculate her net profit or loss after tax and all deductions. Turnover is another word for sales or revenue. It is the amount of money taken by a business in a period. SLIDE 30 The same young girl decides to expand her business a second time. She buys 10,000 kg of sweets for £15,000. She buys sufficient boxes for £600. She pays several boys to pack the boxes each containing 250g of sweets, giving them a wage of £8 per hour. They pack the boxes at 50 per hour. She sells the sweets for 95p per box. The government gets wind of her business and imposes a social security payment of £1 per hour worked by the boys; then a 4/10 tax on her profits before social security is taken off, and a fine of £20,000 for not declaring her turnover. Calculate her net profit or loss after tax and all deductions. Solution Number of sales Hours worked Wage costs Costs Revenue Profit before charges Tax: £6,400, Social security: £800, Fine: £20,000 Charges Net loss SLIDE 29B The same young girl decides to expand her business a second time. She buys 10,000 lb of sweets for $15,000. She buys sufficient boxes for $600. She pays several boys to pack the boxes each containing 4 oz of sweets, giving them a wage of $8 per hour. They pack the boxes at 50 per hour. She sells the sweets for 95¢ per box. The government gets wind of her business and imposes a social insurance payment of $1 per hour worked by the boys; then a 4/10 tax on her profits before social insurance is taken off, and a fine of $20,000 for not declaring her turnover. Calculate her net profit or loss after tax and all deductions. Turnover is another word for sales or revenue. It is the amount of money taken by a business in a period. SLIDE 30B Solution Number of sales Hours worked Wage costs Costs Revenue Profit before charges Tax: $6,400, Social insurance: $800, Fine: $20,000 Charges Net loss SLIDE 31 Speedy Deliveries buy a van for £16,500 plus sales tax of £3,300. They make a down-payment for the van of £4,200. They pay the balance in 12 equal instalments. How much is each instalment? A down-payment is an initial payment for a purchase. The rest of the purchase is bought on credit and paid for in instalments. SLIDE 32 Speedy Deliveries buy a van for £16,500 plus sales tax of £3,300. They make a down-payment for the van of £4,200. They pay the balance in 12 equal instalments. How much is each instalment? Solution Each instalment is £1,300 SLIDE 31B Speedy Deliveries buy a van for $16,500 plus sales tax of $3,300. They make a down-payment for the van of $4,200. They pay the balance in 12 equal instalments. How much is each instalment? A down-payment is an initial payment for a purchase. The rest of the purchase is bought on credit and paid for in instalments. SLIDE 32B Solution Each instalment is $1,300 SLIDE 33 A High School puts on a production of West Side Story. They charge admission. The expenses of the production are £1,300. When 300 tickets were sold, the School made a profit of £1,700. What will be the profit in a second similar production if 450 tickets are sold, assuming the same costs? SLIDE 34 A High School puts on a production of West Side Story. They charge admission. The expenses of the production are £1,300. When 300 tickets were sold, the School made a profit of £1,700. What will be the profit in a second similar production if 450 tickets are sold, assuming the same costs? Solution Costs per ticket Sales of second production Profit of second production SLIDE 33B A High School puts on a production of West Side Story. They charge admission. The expenses of the production are $1,300. When 300 tickets were sold, the School made a profit of $1,700. What will be the profit in a second similar production if 450 tickets are sold, assuming the same costs? SLIDE 34B Solution Costs Sales of second production Profit of second production