Question

A 150-pound person uses 5.4 calories per minute when walking at a speed of 4 mph. How long must a person walk at this speed to use at least 170 calories? A person must walk for at least minutes in order to use at least 170 calories. (Round up to the nearest minute ces

Answer 1

The person uses 5.4 calories in 1 minute.

To find how many minutes the person needs to use 170 calories, we can use the next proportion:

$\frac{5.4\text{ calories}}{170\text{ calories}}=\frac{1\text{ minute}}{x\text{ minutes}}$

Solving for x,

$\begin{gathered} 5.4\cdot x=1\cdot170 \\ x=\frac{170}{5.4} \\ x\approx32\text{ minutes} \end{gathered}$

A person must walk for at least 32 minutes in order to use at least 170 calories.