If a train runs with the speed of 72 km/h, it reaches its destination late by 15 minutes. However, if its speed is 90 km/h, it is late by only 5 minutes. The correct time to cover its journey in minutes is:
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 35
The ratio of the speeds = 72 : 90 = 4 : 5
As distance is constant,
The ratio of their time = 5 : 4.
According to the question,
5x - 4x = 15 - 5
x = 10 minutes
5x = 5 × 10 = 50 minutes.
Correct time = 50 - 15 = 35 minutes.