Question

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?

• A. 6.75
• B. 6
• C. 6.5
• D. 6.25

Answer 1

Answer:

D. 6.25

Find total distance

Speed = 50 km/h, Time = 4.5 h
Distance = (50 \times 4.5 = 225) km

New time

Saved time = 30 min = 0.5 h
New time = (4.5 - 0.5 = 4) hours

New speed

$\text{New speed} = \frac{225}{4} = 56.25 \text{ km/h}$
Increase in speed

$56.25 - 50 = 6.25 \text{ km/h}$