the price went up a book went up from $20 to $25 by how many percent did the price increase

Answer 1

To find the percent increase, use this formula.

% increase = new number - original number x 100

original number

% increase = 25 - 20 x 100

20

% increase = 5 x 100

20

% increase = 0.25 x 100

% increase = 25%

Answer 2

What you are looking for here is the percent increase. There is a formula for this that will be useful to memorize if you can. This is the formula:

(X₂ - X₁)/X₁ * 100%, where X₁ = the original price

X₂ = the new price

What this formula means is the difference between the new price and the original price, divided by the original price, and then multiplied by 100 to gives us the percentage value. Now that you have the formula, just plug in the numbers you are given. To make things easier, I always save the multiplying by 100 step for last.

In this example, the original price X₁ = 20.

The new price X₂ = 25.

Plugging these numbers in gives us:

(25 - 20)/20 = 5/20 = 1/5 = 0.20

Now let's multiply this number by 100%.

0.20 * 100% = 20%.

And there you have it, a 20% increase.