Percentage change quiz

Question 1

Increase $300 by 10%

Answer 1

10% of $300 = 10/100 * $300

= $30

New Amount = $300 + $30

= $330

Question 2

Decrease 400 cm by 20%

Answer 2

20% of 400 = 20/100 * 400

= 80 cm

New Amount = 400 cm - 80 cm

= 320 cm

Question 3

Ali scored 60 marks in the last test. His marks increased by 30%. What is new marks?

Answer 3

30% of 60 = 30/100 * 60

= 18

New Amount = 60 + 18

= 78

Question 4

A bottle has 1000 ml of water. 25% was spilled. What is the amount of water left?

Answer 4

25% of 10000 = 25/100 * 1000

= 250 ml

New Amount = 1000 - 250

= 750 ml

Question 5

What is the percentage increase when 8 increases to 12

Answer 5

increase = 12 - 8

= 4

% increase = 4/8 * 100

= 50%

Question 6

What is the percentage increase when 20 cm increases to 25 cm

Answer 6

increase = 25 - 20

= 5 cm

% increase = 5/20 * 100

=25%

Question 7

What is the percentage decrease when 20 decrease to 12

Answer 7

decrease = 20 - 12

= 8

% increase = 8/20 * 100

= 40%

Question 8

What is the percentage decrease when 70 kg decrease to 63 kg

Answer 8

decrease = 70 - 63

= 7 kg

% increase = 7/70 * 100

= 10%

Question 9

The plant grew by 15% to 230 cm. What was the plant’s orignial height?

Answer 9

15 + 100 = 115%

115 % is 230 cm

1% is 230/115 = 2 cm

100% is 2 * 100 cm = 200 cm

Question 10

Mary’s weight is now 60 kg after a 20% weight loss, What was her orginal weight?

Answer 10

100 -20 = 80%

80 % is 60 kg

1% is 60/80 = 0.75 kg

100% is 0.75 * 100 kg = 75 kg