Answers − Percentage Change

1.   The original price is 500 and the new price is 700.

  Find the percentage increase

(a)   the increase amount is 700 − 500 = 200

(b)   the percentage as a fraction is 200/500 = 2/5

(c)   100 ÷ 5 = 20 (where 5 is the demoninator of the fraction)

(d)   2/5 × 20/20 = 40/100 = 40%

So 40% increase in price

2.   The original price is 470 and the new price is 564.

  Find the percentage increase

(a)   the increase amount is 564 − 470 = 94

(b)   the percentage as a fraction is 94/470 = 1/5

(c)   100 ÷ 5 = 20 (where 5 is the demoninator of the fraction)

(d)   1/5 × 20/20 = 20/100 = 20%

So 20% increase in price

3.   The original price is 50 and the new price is 40.

  Find the percentage decrease

(a)   the decrease amount is 50 − 40 = 10

(b)   the percentage as a fraction is 10/50 = 1/5

(c)   100 ÷ 5 = 20 (where 5 is the demoninator of the fraction)

(d)   1/5 × 20/20 = 20/100 = 20%

So 20% decrease in value.

4.   The original price is 1100 and the new price is 990.

  Find the percentage decrease

(a)   the decrease amount is 1100 − 990 = 110

(b)   the percentage as a fraction is 110/1100 = 1/10

(c)   100 ÷ 10 = 10 (where 10 is the demoninator of the fraction)

(d)   1/10 × 10/10 = 10/100 = 10%

So 10% decrease in value.

         back to: