Correct Answer - Option 4 : 1600 km
Given:
Speed of the express train = 70 km/hr
Speed of the Rajdhani train = 90 km/hr
Concept:
In these types of questions, we find the time when they meet with the help of relative speed concept and then we find the distance between Delhi and Mumbai.
Formula:
Relative speed = S1 + S2 (when trains move in the opposite direction)
Relative speed = S1 – S2 (when trains move in the same direction)
Distance = speed × time
Calculation:
let the time when they meet be x hrs
According to the question,
The faster train travels 200 km more than slower train
⇒ 200 = (90 – 70) × x
⇒ x = 200/20 = 10 hrs
Distance travelled by trains in 10 hrs = (90 + 70) × 10
= 1600 km
∴ Distance between Delhi and Mumbai = 1600 km