Correct Answer - Option 4 : 180 km
The ratio of speed, original to after = 1 : 2
⇒ The ratio of time, actual to after = 2 : 1
As we know, time is inversely proportional to speed.
2 - 1 = 1 unit
⇒ 1 unit = 2 hr 15 min = 2 + 1/4 = 9/4 hr
⇒ 2 unit = 2 × 9/4 = 9/2 hr
∴ Distance covered by train in 9/2 hr with the speed of 40 km/hr = 40 × 9/2 = 180 km
