Question

Aman cycled to school everyday at the speed of 10 km/hr and usually took 20 minutes to reach it. One day, he was late so he managed to reach his school in 10 minutes. What was his speed?

• A. 30 km/hr
• B. 20 km/hr
• C. 10 km/hr
• D. 15 km/hr

Answer 1

The correct option is B 20 km/hr

If Aman cycles at a higher speed, he will reach his school in less time.
$\therefore$ This is a case of inverse proportion.
Using the formula for inverse proportion,
$Speedofcycling\times Timerequired=constant$
$\Rightarrow 10\times 20=Speedofcycling\times 10$
$\therefore Speedofcycling=\frac{10\times 20}{10}=20km/hr$.