Chapter 4.5, Problem 41SR

To determine

If the person drove 248 miles in 4 hours then at that rate how long it will take to drive an additional 93 miles.

Answer to Problem 41SR

At same rate the person takes 1.5 hours to drive additional 93 miles.

Explanation of Solution

Given information:It is given that the person drives 248 miles in 4 hours.

Formula used:The relation between distance $\left(d\right)$ , time $\left(t\right)$ and speed $\left(s\right)$ is given as

  $\text{Speed}\left(s\right)=\frac{\text{Distance}\left(d\right)}{\text{Time}\left(t\right)}\mathrm{......}\left(1\right)$

Calculation: When distance $\left(d\right)$ is 248 miles and time $\left(t\right)$ is 4 hours then speed $\left(s\right)$ is evaluated as

  $\begin{array}{c}\text{Speed}\left(s\right)=\frac{\text{Distance}\left(d\right)}{\text{Time}\left(t\right)}\mathrm{......}\left(\text{Using }\left(1\right)\right)\\ =\frac{248}{4}\\ =62\text{miles/hour}\end{array}$

Now, when speed $\left(s\right)$ is 62 miles per hour and distance $\left(d\right)$ is 93 miles then time $\left(t\right)$ is evaluated as,

  $\begin{array}{c}\text{Speed}\left(s\right)=\frac{\text{Distance}\left(d\right)}{\text{Time}\left(t\right)}\mathrm{......}\left(\text{Using }\left(1\right)\right)\\ 62=\frac{93}{\left(t\right)}\\ \text{or, }t=1.5\text{ hours}\end{array}$