 # Math: Middle School: Grades 6, 7 and 8 Quiz - Numbers - Percentages - Increases and Decreases 1 (Questions)

This Math quiz is called 'Numbers - Percentages - Increases and Decreases 1' and it has been written by teachers to help you if you are studying the subject at middle school. Playing educational quizzes is a fabulous way to learn if you are in the 6th, 7th or 8th grade - aged 11 to 14.

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You will often have to find a value when an amount increases or decreases by a percentage. There is more than one way of working it out.

Try this Math quiz about percentages and numbers to get you familiar with the methods.

1. 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
2. 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
3. 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
4. To find the result of increasing a number by 13% you multiply it by .......
 [ ] 1.13 [ ] 1.3 [ ] 1.31 [ ] 87
5. To find the result of decreasing a number by 7% you multiply it by .......
 [ ] 0.9 [ ] 0.93 [ ] 1.07 [ ] 1.7
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
7. 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
8. To find the result of increasing a number by 66% you multiply it by .......
 [ ] 1.16 [ ] 1.6 [ ] 1.66 [ ] 34
9. 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 soccer 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 Math: Middle School: Grades 6, 7 and 8 Quiz - Numbers - Percentages - Increases and Decreases 1 (Answers)
1. 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
2. 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
3. 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
4. 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)
5. 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)
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 [x] £23,490
7. 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
8. 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
9. 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
10. The local soccer 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