Question

After $3$ months on a diet, Lisa had lost $12\%$ of her original weight. She lost $21$ pounds. What was Lisa’s original weight?

Short answer

Lisa's original weight is$175$pounds.

Step-by-step solution

Step 1. Given Information  

Lisa has lost $21$pounds of weight and after $3$months on a diet, she had lost $12\%$of her original weight. We have to find Lisa's original weight.

Step 2. Translate into an equation 

Let xbe the original weight.

Lisa had lost $12\%$of her original weight and she lost$21$pounds.

So, the equation is

$\left(12\%\right)·x=21$

Step 3. Solve the equation 

By proceeding with the calculation further

$$\begin{gathered} \left(12\%\right)·x=21 \\ \left(0.12\right)x=21 \\ x=\frac{21}{0.12} \\ x=175 \end{gathered}$$

Step 4. Check the answer  

So, yes $12\%\mathrm{of}175\mathrm{is}21.$

Thus, Lisa's original weight is$175$pounds.