We are asked to find 90 % of the number, of which 60 % is 18. To do so, we can start by finding the number of which 60 % is 18. Then we will find 90 % of that number. Recall that we can use the percent equation to solve problems that involve percent.
Percent Equation [0.3em]
part = percent * whole
We want to find the number of which 60 % is 18, which means that we want to find the whole. Let w represent the whole.
18 = 60 % * wBefore we can solve the equation that we got, we need to write the percent as a decimal. We can write a percent as a decimal by ignoring the percent symbol and moving the decimal point two places to the left.
We got that 60 % is equal to 0.60 or 0.6.
18 = 60 % * w [0.3em] ↓ [0.3em]
18 = 0.6 * w
Now let's solve the equation for w. To do so, we will use the Division Property of Equality.
We found that w= 30 is a solution to the equation. This means that 18 is 60 % of 30. Next, we will find 90 % of 30. To do so, we can once again use the percent equation. In this case, the whole is 30. Let p represent the part.
part = percent * whole [0.3em] ↓ [0.3em]
p = 90 % * 30
Before we can solve the equation that we got, let's write the percent as a decimal the same way we did before.
We got that 90 % is equal to 0.90 or 0.9.
p = 90 % * 30 [0.3em] ↓ [0.3em]
p = 0.9 * 30
Finally, let's solve the equation for p.
