By what percentage should a car driver increase the speed of the car to reduce the time by 40% to cover a fixed distance?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 66%.
According to the question,
Distance is fixed
Let the required time be t
So, reduced by 40% = 60/100 × t = 3t/5
Distance = Speed × Time
Original speed × t = New speed × 3t/5
Original speed/New speed = 3t/5 × 1/t
Original speed/New speed = 3/5
Required percentage = 2/3 × 100 = 200/3 = 66%