Correct Answer - Option 3 : 90 km
Given:
Speed of trains are 45 m/sec & 25 m/sec
Concept used:
Time taken = d/(s1 – s2)
(Moving in same direction)
d = distance covered
s1 = Speed of train 1
s2 = Speed of train 2
Calculation:
{d/(45 – 25)} = 75
⇒ d/20 = 75 × 60
⇒ d = 20 × 4500 = 90000 m = 90 km
∴ The distance between the trains after 75 minutes is 90 km.