Question

A girl is cycling and she covers 0.5 km in 2 minutes, next 0.75 km in 3 minutes and last 1 km in 4 min. Her average speed is.

• A. 4.16 m/s
• B. 8.24 m/s
• C. 9 m/s
• D. 6.32 m/s

Answer 1

The correct option is A 4.16 m/s

In the first part of the journey, the distance covered is 0.5 km and time is 2 min.
In the second part of the journey, the distance covered is 0.75 km and time is 3 min.
And, In the third part of the journey, the distance covered is 1 km and time is 4 min.
So, the total distance covered is 2.25 km and the total time is 9 min.

$\text{Average speed}=\frac{\text{Total distance}}{\text{Total time}}=\frac{2.25}{9}=0.25\text{km/min}$
$1\text{km}=1000$ m and $1\text{min}=60$
So average speed in $\text{m/s}$ $=\frac{0.25\times 1000}{60}=4.16\text{m/s}$