Question

A car, while running at a speed of 40 kmph covers a certain distance in 10 hours and a bus covers the same distance in 8 hours. Find the percentage by which the speed of the car is less than the speed of the bus.

• A. 25%
• B. 20%
• C. 33.33%
• D. 66.66%

Answer 1

The correct option is B 20%

Total distance covered by car = 10 × 40 = 400 km

Now, let the speed of the bus be B kmph.

So, 8 × B = 400

⇒ B = 50,

i.e., the speed of the bus is 50 kmph.

So, the speed of the car is less than that of the bus by (50 – 40) kmph = 10 kmph

Required answer $=\frac{10}{50}\times 100$% =20%

Alternate method:
The car takes 10 hours and the bus takes 8 hours to cover the same distance,

i.e., the time taken is in the ratio of 10:8 = 5:4

So, the speeds of car and bus will be in the ratio of 4 5 (because time taken is inversely proportional to the speed).

So, the speed of the car is 20% less than that of the bus.

Hence, option B is the correct answer.