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A train's top speed is 140 mph. Find out more in this quiz.

Level 5-6 Numbers - Percentages - Increases and Decreases

Percentages are a crucial skill you'll use a lot in real life - like wage increases, inflation rates, and interest rates. No wonder they're a big part of KS3 Maths. This quiz focuses on calculating increases and decreases in terms of percentages.

1.
To find the result of increasing a number by 13% you multiply it by .......
1.13
1.3
1.31
87
If something is increased by x% then its original value will have to be multiplied by (1 + x) to find the new value. The 1 represents 100% and the x represents the percentage increase: in this case (1 + x) = (1 + 0.13) = 1.13. If there was a decrease of x%, then you would have to multiply the original value by (1 - x)
2.
The local football team are playing badly and the number of season tickets sold reduces by 17% from last year. If 3,700 tickets were sold last year, how many were sold this year?
3,000
3,071
3,091
3,099
To find 17% multiply by 0.17
3.
Harold owns a 14% stake in a company worth £250,000. How much is Harold's stake worth?
£35,000
£40,000
£45,000
£50,000
To find 14% multiply by 0.14
4.
A train's top speed is 140 mph. After a service, its top speed increases by 12%. What is the new top speed?
150 mph
156 mph
156.4 mph
156.8 mph
A 12% increase is a multiplier of 1.12. 1.12 x 140 = 156.8
5.
To find the result of increasing a number by 66% you multiply it by .......
1.16
1.6
1.66
34
Calculations are much easier if a multiplier is used
6.
Thomas earns £22,500 per year. He receives a pay rise of 4.4%. How much does he now earn?
£23,000
£23,400
£23,450
£23,490
4.4% of 22,500 is 990. To work this out you could multiply 22,500 x 0.044 (4.4 hundredths)
7.
In a sale, all the prices are reduced by 20%. Find the sale price of a washing machine which originally cost £299.
£60
£100
£176.30
£239.20
One way is 20 / 100 x £299 = £59.80. Then subtract £59.80 from £299 to get £239.20
8.
To find the result of decreasing a number by 7% you multiply it by .......
0.9
0.93
1.07
1.7
Percentages are easily converted to decimals. Just divide by 100 (or move digits)
9.
Bob, the local car dealer, is reducing all his cars by 15%. Find the reduced price of a Nissan which originally cost £690.
£580.60
£585.50
£586.50
£590.90
Another way is to use a multiplier. A 15% decrease is a mutliplier of 100 - 15 = 85%. 85% = 0.85 (just divide 85 by 100). £690 x 0.85 = £586.50
10.
Simon bought his computer for £230. A year later he sold it for 20% less than he paid for it. How much was it sold for?
£164
£184
£204
£224
To work out 20% just divide by 5