Question

Anna takes 2 hours to travel from Delhi to Agra at the rate of 60 Km/hr. She decreases her speed by 50% and takes three hours to travel from Agra to Chandigarh. Find the average speed from Delhi to Chandigarh.

1. 24 km/hr
2. 30 km/hr
3. 50 km/hr
4. 42 km/hr
5. 72 km/hr

Answer 1

Correct Answer - Option 4 : 42 km/hr

Formula Used:

Average speed = Total distance travelled/Total time

Calculations:

Speed (from Delhi to Agra) = 60 Km/hr

Speed (from Agra to Chandigarh) = 60 – 50% of 60 Km/hr

⇒ 30 km/hr

Distance from Delhi to Agra = speed × time

⇒ 60 × 2 = 120 km

Distance from Agra to Chandigarh = speed × time

⇒ 30 × 3 = 90 km

Total Distance = 120 + 90 = 210 km

Total Time = 2 + 3 = 5 hr

Average speed = 210/5 = 42 Km/hr

Hence the average speed from Delhi to Chandigarh is 42 Km/hr.