Question

A downhill skier is travelling at a rate of 0.5 miles per minute. How far will the skier travel in 18 minutes?

Answer 1

Hint: The formula that relates the distance, speed and time should be used to solve this problem. The values of the speed, that is the rate and the time taken are given, so, by dividing these values we will get the value of the distance covered by the downhill skier.
Formula used:
\[s=\dfrac{d}{t}\]

Complete answer:
From the given information, we have the data as follows.
A downhill skier is travelling at a rate of 0.5 miles per minute, that is, \[s=0.5{mile}/{\min }\;\]
The time taken is 18 minutes, that is, \[t=18\,\min \]
The speed is given in terms of miles per minute and the time taken is also given in terms of minutes, so, there is no need to convert the unit of the time to seconds, as the unit of time gets cancelled out.
We are asked to find the distance covered by the downhill skier in 18 minutes.
The formula that relates the distance, speed and time is given as follows.
\[s=\dfrac{d}{t}\]
Where s is the speed, d is the distance and t is the time taken.
Substitute the given values in the above equation to find out the value of the distance covered by the downhill skier.
\[\begin{align}
  & 0.5=\dfrac{d}{18} \\
 & \Rightarrow d=0.5\times 18 \\
 & \therefore d=9\,mile \\
\end{align}\]
\[\therefore \]The distance covered by the downhill skier is 9 miles in 18 minutes.

Note:
Even though mile is not a SI unit, we haven’t converted it into an SI unit, as in question they didn’t ask to convert the unit. The distance is the speed by time. The unit of speed is in minutes and even the time is in minutes, so gets cancelled out, thus no need to change.