Q18. - Algebra 1

Question

Use the percent proportion to find the following number.

5% of what number is 3.5?

Step-by-Step Solution

Answer

5% of 70 is 3.5.

Step 1. Definition of percent.

Percent of a number is defined as the ratio of number and 100.

Step 2. Formula Used.

The ratio of part x of some number y is equal to the percent is written as.

$\frac{x}{y}=\frac{p}{100}$

Step 3. Find the percent proportion.

x = 3.5, percent = 5 and y =?

$$\begin{gathered} \frac{x}{y} =\frac{p}{100} \\ \frac{3.5}{y}=\frac{5}{100} \left[\mathrm{crossmultiply}\right] \\ 3.5\times 100=5y \\ 350=5y \left[\mathrm{dividebothsideby}5\right] \\ \frac{350}{5}=\frac{5y}{5} \\ 70=y \\ y=70 \end{gathered}$$

Hence, 5 percent of 70 is 3.5.