Question

Rohit takes 2 hours to reach the airport travelling at a speed of 40 km/h. At what speed should Rohit travel to reach the airport in 80 min?

Answer 1

Let x be the speed required to reach airport in 80 min.

Time taken (in min)	Speed (in km/h)
120	40
80	x

Time taken and speed are in inverse variation.
So, using arrow method:
$\frac{120}{80}=\frac{x}{40}$
On cross multiplication,
$x=\frac{120}{80}\times 40=60$
So, the required speed is 60 km/h.