The distance from Chandigarh to Amritsar is covered in 4.5 hours at a speed of 50 km/hr. By how much should the speed (in km/hr) be increased to save 30 minutes of travel time?

Correct option is D

Given:
Distance from Chandigarh to Amritsar is covered in 4.5 hours at 50 km/hr.
Time to be saved = 30 minutes = 0.5 hours
Required: Increase in speed (in km/hr) to save 30 minutes.
Formula Used:
Distance = Speed × Time
Solution:
Distance using original speed and time = 50 × 4.5 = 225 km
New Time (in order to save 30 minutes) = 4.5 – 0.5 = 4 hours
New Speed = 225 ÷ 4 = 56.25 km/hr
Required increase in speed = 56.25 – 50 = 6.25 km/hr