Chapter 11.1, Problem 92E

Food versus Recreation The following equation shows the approximate relationship between the percentage y of total personal consumption spent on food and the corresponding percentage x spent on recreation.

$y=\frac{688}{x^{1.99}}\text{ percentage points }\left(4.83\le x\le 9.35\right)$

According to the model, spending on food is decreasing at a rate of $\_\_\_\_\_$ percentage points per 1 percentage point increase in spending on recreation when 6.0% of total consumption is spent on recreation. (Your answer should be rounded to two significant digits.) [HINT: See Example 2(b).]