Question

A car takes 2 hours to reach a destination by travelling at the speed of 60 km/h. how long will it take when the car travels at the speed of 80 km/h?

Answer 1

Let the time taken by the car to reach the destination, while travelling with a speed of 80 km/hr, be x hours. 
The following table is obtained.

Speed (in km/hr)	60	80
Time taken (in hours)	2	x

More the speed of the car, lesser will be the time taken by it to reach the destination.
Hence, the speed of the car and the time taken by the car are inversely proportional to each other. 
Therefore,
\(60 × 2 = 80× x\)
\(x=\frac{60 × 2 }{ 80}\)
\(x=\frac{3}{2} = 1 \frac{1}{2}\)
The time required by the car to reach the given destination is \(1 \frac{1}{2}\) hours.