SSC CPO 2023 PYQ — Question 138

The correct answer is option 2 i.e. 5 hours.

The distance travelled by train = 1000 km

Its average speed for the trip was reduced by 75 km/h, and the time of travel increased by 3 hours.

Time taken = $Distance \over speed$

Let the original speed be x km/h.

According to the question

⇒ ${1000\over (x - 75)} - {1000\over x}$ = 3

⇒ x (x - 75) = 25000

⇒ x = 200 km/h

Hence, the original duration of the travel is given by,

⇒ $1000\over 200$ = 5 hours.