Question

kelly reduced the size of a portrait to have a width of 10 inches. if she used a scale of 1 inch : 2 inches, what was the width of the original portrait?

Explanation:

Step1: Define the scale proportion

Let $x$ = original width. The scale means $\frac{\text{reduced width}}{\text{original width}} = \frac{1}{2}$, so $\frac{10}{x} = \frac{1}{2}$

Step2: Solve for original width

Cross-multiply to isolate $x$: $x = 10 \times 2$

Answer:

20 inches