Chapter 8.4, Problem 60CCR

To determine

Which of the three friends to walked at the fastest rate.

Answer to Problem 60CCR

Sumitra

Explanation of Solution

Given:

The table shows the time it took three friends to walk different distances.

  

Calculation:

In order to find which of the three friends to walked at the fastest rate, use the time-distance formula and find the speed of each of them. Observe that $\text{Speed=}\frac{\text{Distance}}{\text{Time}}$ , so using this formula, the speed of Jonathan, who covered 1/4 miles in 1/8 hours is given by

  $\begin{array}{c}\text{Speed}=\frac{\text{Distance}}{\text{Time}}\\ =\frac{1/4}{1/8}\\ =\frac{1}{4}\cdot \frac{8}{1}\\ =\frac{8}{4}\\ =2\text{ miles per hour}\end{array}$

Similarly, Sumitra covered 2/3 miles in 1/6 hours, so her speed is

  $\begin{array}{c}\text{Speed}=\frac{\text{Distance}}{\text{Time}}\\ =\frac{2/3}{1/6}\\ =\frac{2}{3}\cdot \frac{6}{1}\\ =\frac{12}{3}\\ =4\text{ miles per hour}\end{array}$

And, Leah who covered 1/2 miles in 1/6 hours, his speed is

  $\begin{array}{c}\text{Speed}=\frac{\text{Distance}}{\text{Time}}\\ =\frac{1/2}{1/6}\\ =\frac{1}{2}\cdot \frac{6}{1}\\ =\frac{6}{2}\\ =3\text{ miles per hour}\end{array}$

So out of the three, Sumitra walked at the fastest rate.