# On the first day of the semester, Shay scored a 60 on a math pre-test. On the last day of the same semester, Shay scored a 75 on the post-test. By what percent did Shay's score improve?

Nov 28, 2016

Shay's score improved by 25%.

#### Explanation:

To measure the percentage change you use the formula:

$p = \frac{N - O}{O} \cdot 100$ where $p$ is the percentage change, $N$ is the new value and $O$ is the old value.

In this problem we are given the Old score (60) and the New score (75) which we can substitute into the formula and solve for $p$:

$p = \frac{75 - 60}{60} \cdot 100$

$p = \frac{15}{60} \cdot 100$

$p = \frac{1500}{60}$

$p = 25$