Question

The cost of a stereo cable has risen to $21 today. Yesterday's cost was $16 . Find the percentage increase. Round your answer to the nearest tenth of a percent.

Answer 1

31.3%

Explanation:

So today's % price at $21

Yesterday, the original 100% price was $16

Using a ratio

$16. 100%

------. =. --------

$21. x

Now we can cross multiply and divide

Cross multiplication gets you...

16x = 2100

Dividing both sides by 16 to get x alone

x = 2100/16

x = 131.25

Now to find the percent we subtract this from 100

131.25 - 100 = 31.25 which equals 31.3%