A racing car going at an average speed of 108 km/hr takes 15 minutes to complete a lap on a racing track. By how much should it increase its speed (in km/hr) to complete the lap in 12 minutes?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 ie 27
Distance of the lap = 108 × (1/4) = 27 km
Time to complete the lap = 12 min = 1/5 hour
Speed = 27/(1/5) = 135 km/hr
Increase = 135 - 108 = 27 km/hr