# CLASS-8PERCENTAGE CHANGE IN A QUANTITY

PERCENTAGE CHANGE IN A QUANTITY

To find the percentage change in a quantity, to find the percentage change in a quantity, write the change in the quantity as the numerator and the original quantity as the denominator, and then multiply the fraction by 100.

Change in the quantity

Percentage Change =  ----------------------- X 100

Original quantity

Example.1)  If the number of Kangaroo in Australia was 1500 in the year 2009 and 2000 in the year 2010 then an increase in the number of kangaroos =  2000 – 1500 = 500

So, percentage change ( or increase )

500

= ---------- X 100

1500

100

=   ----------- =  33.33 %          (Ans.)

3

If a quantity decreased by x%

x

New quantity =  ( 1 - -------- ) X original quantity

100

New quantity

Original quantity  =  ----------------------------

x

( 1 - -------- )

100

If a quantity increased by x%

x

New quantity =  ( 1 + -------- ) X original quantity

100

New quantity

Original quantity  =  --------------------------

x

( 1 +  -------- )

100