Question

Meenakshee cycles to her school at an average speed of 12 km/hr and takes 20 minutes to reach her school. If she wants to reach her school in 12 minutes, her average speed should be:

• A. $\frac{20}{3}$ km/hr
• B. 16 km/hr
• C. 20 km/hr
• D. 15 km/hr

Answer 1

The correct option is C

20 km/hr

If the time taken decreases, then speed will increase. It is a case of inverse proportion.
$\begin{array}{ccc}Speedofcar\left(km/hr\right)& 12& X\\ Timetaken\left(mins\right)& 20& 12\end{array}$

Then, $12\times \frac{20}{60}=x\times \frac{12}{60}x=12\times \frac{20}{60}\times \frac{60}{12}=20km/hr$