## Thinking Mathematically (6th Edition)

The statement does not make sense. Let $I$ be the person's income. The rent increased from $0.2I$ to $0.3I$. The increase in rent is $0.1I$. We can express this increase as a percent. $\frac{increase}{original~rent} = \frac{0.1I}{0.2I} = 0.5 = 50\%$ The percent increase is 50%