% Type 4 - Percent Change

% Solved!

Type #4

The percent change. D’oh!

This is the “donuts rose from 75¢ each to 90¢ each” type of question. You will be asked to find out what percent the price rose. This is a fairly common percentage question and one that is often used to explain how much prices or salaries have risen or fallen.

I have:                         1 number

I have:                         A 2^nd number

I need to find:            The percentage value for the difference between the 2 numbers.

Example:              a) Donuts rose from 75¢ each to 90¢ each. What  percentage did the price rise?

Key to Solving:

The price of doughnuts went up! D'oh!    D’O   Homer Simpson saves the day! The key to solving these questions is Difference ÷ The Original

Step 1 – Calculate the Difference.      90¢ - 75¢ = 15¢.

Step 2 – Divide 15¢ by the Original price, which is 75¢. Note – the 90¢ does not appear in the calculation below. It only played a part in calculating the difference.

Step 3 –       15¢    X  100% = 20%  

                   75¢.

Donuts rose by 20%. (Was it the extra baking powder?)

 Tricks to look out for.

 Remember to concentrate on which value is the Original price. It is not necessarily the smaller of the 2 prices.

a) A price decreased from $50.00 to $40.00. What is the percentage of change?

ý Wrong! 10  X  100%  = 25%

                   40               

þ Right!   10   X  100% = 20%. The price decreased by 20%

       50 

The original price was $50.00