The simplest way to do this is, first, to find the difference between the two values. 8.50 - 5.10 = 3.40
Then, just find $3.40 as a percentage of the original value, $5.10, to find the increase. 3.4 / 5.1 = 0.6 recurring ---> Multiply this by 100 to find the percentage. 0.6 recurring x 100 = 66.7% (to the nearest tenth of a percent)
The increase was 66.7%, to the nearest tenth of a percent.
