Question

A rock climber's elevation above sea level changed −82 1/2 feet in 2 1/4 minutes as she descended.

Answer 1

Answer:

$-36\frac{2}{3}ft/min$

Step-by-step explanation:

The elevation changed $-82\frac{1}{2} ft$ in $2\frac{1}{4} min$. To find the ratio of change of such elevation, we just have to divide these quantities. However, we need to transform each mixed number into a fraction, as follows

$-82\frac{1}{2} ft=-\frac{165}{2} ft\\2\frac{1}{4} min=\frac{9}{4}min$

Then, we divide

$-\frac{165}{2}ft \div \frac{9}{4} min=-\frac{165}{2}ft\times \frac{4}{9}\frac{1}{min}=-\frac{660}{18}ft/min=-36\frac{12}{18} =-36\frac{2}{3}ft/min$

Therefore, the ratio of change expressed as a mixed number is

$-36\frac{2}{3}ft/min$

Answer 2

What was the climber's average change in elevation per minute?
-36⅔