Finding a Number when Part and Percent are Known

In this scenario, the problem is only asking for the Whole as the percent and the Part are known.

Example:

                14 is 25% of what number?

Solution

1) 25% = %, and 14 = part

2)  Rewrite the proportion. Make the whole equals to x

                14/X = 25/100

3) Let’s do the cross-multiplication

                1400 = 25x

4) Solve fox x

                X = 1400/25 = 56

14 is 25% of 56

Example

18 is 15% of what number

Solution

15 % =  percent 18 = part

Rewrite the proportion. Make the whole equals to x

                   18/x = 15/100

 1800 = 15x

solve for x

x = 1800/15

x = 120

This problem can be done this way also:

If 18 is 15% of some number, you must find that number

Write an equation

18 = .15x ( remember 15/100, can also be written this way .15)

Solve for X, by dividing both sides by .15

18/.15 = .15x/.15

18/.15 = x

Therefore X = 120