Question

Sadie bought some shares in December 2010 In 2011 the value of the shares decreased by 10% In 2012 the value of the shares increased by 20% By what percentage did the value of the shares increase in the two years from the end of 2010 to the end of 2012?

Answer 1

The shares increased by 8%

Explanation:

Here, we want to calculate the percentage increase in the value of the shares

Let the original value of the shares bought be $x

It decreased by 10%

Mathematically,

that will be x - (10% of x)

= x -0.1x = 0.9x

This is the new value

It increased at this point by 20%

The new value will be;;

0.9x + (20% of 0.9x)

0.9x + 0.18x

= 1.08x

The percentage increase in the shares will be;

(1.08x - x)/x * 100%

= 0.08x/x * 100% = 8%