Question

Jamal travelled $300$ miles and averaged $60$ miles per hour. How many minutes did he take to complete the trip ?

Answer 1

Hint: The average speed of a body in a certain time interval is the total distance covered by the body in that time interval divided by the time interval so if a particle covers a certain distance \[s\] in a time\[t\] then the average velocity is given by \[{V_{av}} = \dfrac{s}{t}\]. We have distance and average speed is given and we have to calculate the time interval taken by Jamal to cover the given distance.

Complete step by step answer:
Here we have given average speed, and the total distance covered by Jamal in some interval of time and we have to calculate that time interval. Now as we have given that,
Distance travelled Jamal, \[s = 300\,miles\]
Average speed of Jamal, \[{V_{av}} = 60\,miles/h\]
Time travelled by Jamal to cover that distance, \[t = ?\]
From the formula of average speed we have, \[{V_{av}} = \dfrac{s}{t}\]
By changing the sides of average velocity and time in order to obtain the time we have
\[t = \dfrac{s}{{{V_{av}}}}\]
Substituting the values given, we get;
\[t = \dfrac{{300}}{{60}}h\]
On doing simple division we get
\[t = 5\,h\]
Now we know that
\[1\,hour = \,60\,\operatorname{minutes} \]
And so we have
\[t = 5h \\
\Rightarrow t = 5 \times 60\,\min \\
\therefore t = 300\,min \\ \]
Hence Jamal will take 300 minutes to complete the trip of 300 miles at an average speed of 60 miles per hour.

Note: The question might be differ by changing the magnitudes of the quantity. Also there might be change in the unit of measurement like there could be km/h or m/s instead of miles per hour for creating misjudgement in any of the magnitudes. One should also know the difference between average speed and the average velocity in order to solve similar questions in linear line. Average velocity is the total displacement divided by the total time taken.