KS3 numbers percentages increases and decreases

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Maths Quiz - Level 5-6 Numbers - Percentages - Increases and Decreases (Questions)

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.

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Finding a new value when something goes up or down by a percentage can be done in various ways. One easy method is to multiply by a decimal number. For example, if a £200 item has a 5% decrease, multiply £200 by 0.95 (95% of the previous price). For a 5% increase, multiply by 1.05 (105% of the previous price). There are other methods, so feel free to explore!

Practice with this quiz on percentage increases and decreases - use any method you like! Good luck with your KS3 Maths journey!

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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

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

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

To find the result of increasing a number by 13% you multiply it by .......

[ ]	1.13
[ ]	1.3
[ ]	1.31
[ ]	87

To find the result of decreasing a number by 7% you multiply it by .......

[ ]	0.9
[ ]	0.93
[ ]	1.07
[ ]	1.7

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

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 find the result of increasing a number by 66% you multiply it by .......

[ ]	1.16
[ ]	1.6
[ ]	1.66
[ ]	34

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

10.

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

You can find more about this topic by visiting BBC Bitesize - Percentages

Maths Quiz - Level 5-6 Numbers - Percentages - Increases and Decreases (Answers)

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
[x]	£239.20

One way is 20 / 100 x £299 = £59.80. Then subtract £59.80 from £299 to get £239.20

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
[x]	£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

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
[x]	156.8 mph

A 12% increase is a multiplier of 1.12. 1.12 x 140 = 156.8

To find the result of increasing a number by 13% you multiply it by .......

[x]	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)

To find the result of decreasing a number by 7% you multiply it by .......

[ ]	0.9
[x]	0.93
[ ]	1.07
[ ]	1.7

Percentages are easily converted to decimals. Just divide by 100 (or move digits)

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
[x]	£23,490

4.4% of 22,500 is 990. To work this out you could multiply 22,500 x 0.044 (4.4 hundredths)

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
[x]	£184
[ ]	£204
[ ]	£224

To work out 20% just divide by 5

To find the result of increasing a number by 66% you multiply it by .......

[ ]	1.16
[ ]	1.6
[x]	1.66
[ ]	34

Calculations are much easier if a multiplier is used

Harold owns a 14% stake in a company worth £250,000. How much is Harold's stake worth?

[x]	£35,000
[ ]	£40,000
[ ]	£45,000
[ ]	£50,000

To find 14% multiply by 0.14

10.

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
[x]	3,071
[ ]	3,091
[ ]	3,099

To find 17% multiply by 0.17