If a train runs at a speed of 48 km/hr, it reaches its destination late by 12 minutes. However, if its speed is 64 km/hr, it is late by 3 minutes late. The right time to cover its journey (in minutes) is:
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 24.
Let the distance = 'd' km
the actual time taken = 't' hr
⇒ (t + 12/60) × 48 = d
⇒ (t + 3/60) × 64 = d
Equating both the equations:
(t + 1/5) × 48 = (t + 1/20) × 64
⇒ (5t + 1) × 3 = (20t + 1)
⇒ 15t + 3 = 20t + 1
⇒ 5t = 2
⇒ t = 2/5 hr = 24 min