# How do you calculate the percent change of 64 to 80?

Jun 6, 2017

First we need to know the difference between them: $80 - 64 = 16$.

Now we need this difference as a percentage: 16/64 xx100 = 25%

#### Explanation:

We divide by 64 because we want to know how much the number has changed from its original value.

We multiply by 100 because 'per cent' means 'how many out of 100'.

Jun 6, 2017

See a solution process below:

#### Explanation:

The formula for calculating the percent change in a value between two points in time is:

$p = \frac{N - O}{O} \cdot 100$

Where:

$p$ is the percent change - what we are solving for in this problem.

$N$ is the New Value - 80 in this problem.

$O$ is the Old Value - 64 in this problem.

Substituting and solving for $p$ gives:

$p = \frac{80 - 64}{64} \cdot 100$

$p = \frac{16}{64} \cdot 100$

$p = \frac{1600}{64}$

$p = 25$

The percentage change between 64 and 80 is a 25% increase.