PERCENTAGES
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1. Tim bought a new car in 1995 for £10,000 in
2000 the car was priced at £12,500. Calculate the percentage increase in the price of |
£10,000 + (a% of £10,000) = £12,500 Hence a% of £10,000 = £2,500 Using the formula: 10,000 x a/100 =
2,500
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2. "Jeans 'R' Us" have a sale of Jeans and T-shirts,
they have 120 items in the sale. The Jeans and T-shirts are in the
ratio 5 : 3 What percentage of the items in the sale are Jeans? |
In all ratio questions first add the numbers in the ratio: Now work out 120/8 = 15 The number of Jeans = 15 x 5 (answer above x the no. of jeans in the ratio) = 75. So, if we have 75 jeans out of 120, as a percentage this is: 75/120 x 100 = 62.5%
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3. A shop has a 3 day sale where each day, prices are
reduced by 10% of the price on the previous day. Before the start
of the sale a freezer is priced at a) How much is the freezer priced at on the first day of the sale? On the first day of the sale a video recorder is priced at £200. c) How much was the video recorder before the sale?
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a) On the first day we have: £300 - (10% of £300) 10% of £300 = 300 x 10/100 = £30 If £30 is the reduction, the price = £300 - £30 = £270 b) You'll need to calculate the price on the second day first, using the same technique as in a) we get £243. Apply the same technique again and we get £218.70 c) x - (10% of x) = 200 x = 200/0.9 (see earlier answers for explanation) = £222.22 |
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4. Bill shares £180 between his two neices Katie and Amelia. The Ratio of Katie's share to Amelia's share is 5:4. a) How much is Katie given? Katie then gives 10% of her share to Amelia. c) What percentage of the £180 does Amelia now have? |
Add the numbers = 5 + 4 = 9 Divide this into the total = £180/9 = £20 a) Katie is given 5 £20 = £100 b) Amelia is given 4 x £20 = £80 c) 10% of Katie's share is 0.1 x 100 = £10, if this is given to Amelia then Amelia has £80 + £10 = £90. £90 as a % of £180 is 50% (anything that's half of something else is 50%, anything that's a quarter is 25% etc. - remembering the relationship between fractions and percentages can avoid you needing to do any calculations - provided you explain to the examiner how you got your answer!)
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5. The most expensive bike at the mountain bike shop can be bought
for £560 or it can be payed for with a 25% deposit and 10 monthly
payments of £42. |
25% of £560 is the same as 1/4 of 560 = £140 (see question 4) 10 payments at £42 = £420, hence the total for the bike paying over 10 months = £140 + £420 = £560. Hence you pay exactly the same price (no interest)! |
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6. An advertisement for the new multi-media PC says that the computer is only £799.00 (excluding VAT). If VAT is added at the rate of 17.5% of the selling price, how much do you actually have to pay for the computer when VAT is added? |
£799 x 0.175 = £139.83 (this is the amount of VAT you pay to the nearest penny) Total cost = £799 + £139.33 = £938.83 |
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7. After two years the value of a tractor has fallen to £15,000.
After each year passes the depreciation (loss in value) of the tractor
has been calculated at 10%.
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a) x - (10% of x) = £15,000 x = £15,000/0.9 = £16,666.67 b) x - (10% of x) = £16,666.67 x = £16,666.67/0.9 = £18,518.52 |
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8. Business is looking good at "e-Systems" so they have decided to increase their workforce by 20% to cover all the new orders coming in. Before recruiting any new employees, 60 people were working at "e-Systems". a) Assuming the company could recruit all the people they wanted, how many were then working at "e-Systems"?
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20% of 60 = 60 x 0.2 = 12 people a) 60 + 12= 72 people b) Here we have 60 + (75% of 12) = 60 + 3/4 of 12 = 60 + 9 = 69 people |