Page 89 - ICSE Math 8

PRACTICE TIME

1. A given number is increased by 20% and the resulting number is again increased by 15%. What is the
net percentage increase in the number?
2. A given number is increased by 25% and the resulting number is decreased by 25%. What is the net
increase or decrease percentage in the number?
3. A box contains 27 red marbles, 14 green marbles and 13 black marbles. Find the percentage of red marbles
in the box.
4. The sales of a mobile manufacturing company increased by 40% in the first year. In the second year, it
decreased by 30%. Determine the net increase or decrease percentage in the sales.
5. In an annual examination, Ravi scored 81, 67, 78, 92 and 88 marks in Science, English, Hindi, Mathematics,
and Social Science respectively. The maximum marks was 100. Determine the following.
(a) Aggregate percentage scored by Ravi
(b) If the topper scored 93% aggregate, then what percentage of the topper’s aggregate did Ravi score?
6. Mr Jha earns ` 56,500 per month. He gives 10% of it as tax. Out of the remaining he invests 50% in
bonds and from the remaining amount he spends 30% on food and then 20% on shopping. How much
money is he left with?
7. In an annual examination, 41% students scored A in English, 34% scored A in Science and 22% scored
A in both the subjects. Determine the following.
(a) Percentage of total students who did not score an A
(b) Total number of students, if the number of students who scored A in both the subjects is 220
8. A fruitseller bought certain number of mangoes. Later he found that 11% of the mangoes were spoilt.
He sold 60% of the remaining mangoes and is still left with 534 mangoes. How many mangoes did he
purchase initially?
9. Two numbers are 49% and 70% respectively of a third number. Find:
(a) what per cent is the first number that of the second number

(b) what per cent is the second number that of the first number
10. The bill at a restaurant comes to ` 2,500. If you want to give a tip of 15%, how much money should you
give in total?
11. In an election, candidate A got 70% of the total valid votes. 20% of the total votes were declared invalid.
If the total number of votes is 6,00,000, find the number of valid votes polled in favour of the candidate.

THINK SMART

1. A number is increased by 40% and then decreased by 40%. Find the net increase or decrease per cent.
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2. 8 % of all the flowering plants in a garden are roses. If there are 9 rose plants in the garden, how many
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flowering plants are there in all?

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