Question

Train A travelling at 60km/hr leaves Mumbai for Delhi at 6 p.m. Train B travelling at 90 km/hr also leaves Mumbai for Delhi at 9 p.m. Train C leaves Delhi for Mumbai at 9 p.m. If all the three trains meet at the some time between Mumbai and Delhi, then what is the speed of Train C if the distance between Delhi and Mumbai is 1260 km?

• A. 60 km/hr
• B. 90 km/hr
• C. 120 km/hr
• D. 135 km/hr

Answer 1

Answer: (C)

120 km/hr

Answer 2

Distance travelled by train A in 3 hours (till 9 p.m.) travelling at 60 km/hr = 180km
Relative speed of Train A and B travelling in same direction = 90-60=30km/hr
Now, time when train A and train B will meet (Train C will also meet at this point, given) =$\frac{180}{30}=6$ hours
Thus, they will meet at 3 a.m. at a distance of ($90\times6$)=540 km from Mumbai =1260 - 540=720 km from Delhi.
Therefore, Speed of train C $\frac{720}{6}=120$ Km/hr
The correct answer is (C) : 120 km/hr