Worksheet on increase and Decrease Percentage

Practice the questions given in the worksheet on increase and decrease percentage.

We know, to find the increase % the formula is (increase in value/original value) × 100 % and to find the decrease % the formula is (decrease in value/original value) × 100 %.

1. Find the resulting new increased or decreased quantity due to:

(i) 8 % decrease in $ 400

(ii) 5 % increase in 25 km

(iii) 12¹/₂ % increase in a speed of 600 km/h

(iv) 30 % decrease in a temperature of 40° Celsius

(v) 2.5 % increase in a salary of $ 1250

(vi) 2.5 % decrease in 800 gram

2. Find the percentage change from the first quantity to the second quantity:

(i) $75; $90

(ii) 40 cm; 60 cm

(iii) 20 gm; 5 gm

(iv) 60 km/h; 45 km/h

(v) 5 dozen eggs; 100 eggs

(vi) 13.5; 18

3. Increase 150 by 10 % and decrease the same by 15 %. Find the new number in each case.

4. The population of a place in a particular year increased by 15 %. Next year it decreased by 15%. Find the net increase or decrease per cent in the initial population.

5. While measuring a line segment of length 5 cm, it was measured 5.2 cm by mistake. Find the percentage error in measuring the line segment.

6. A number is increased by 40 % and then decreased by 40 %. Find the net increase or decrease per cent.

7. The price of wheat increased by 10 %. By how much per cent should mother reduce her consumption in the house so that her expenditure on wheat does not increase?

8. The salary of a doctor is increased by 40 %. By what per cent should the new salary be reduced in order to restore the original salary?

9. A number 75 is misread as 57. Find the reading error per cent.

Answers for the worksheet on increase and decrease percentage are given below to check the exact answers of the above questions.

Answers:

1. (i) $368

(ii) 26.25 km

(iii) 675 km/h

(iv) 28° Celsius

(v) $1281.25

(vi) 780 gram

2. (i) 20 % increase

(ii) 50 % increase