A car can finish a certain journey in 10 hours at a speed of 42 kmph. In order to cover the same distance in 7 hours, the speed of the car (km/h) must be increased by
Show answer & explanation
Correct answer: C
Explanation
The correct option is 3.
speed = 
distance = speed × time = 10 × 42 = 420 km
to cover the same distance in 7 hours
speed = 
= 60 Km/h
increase in speed = 60 - 42 =18 km/h