Correct Answer - Option 1 : 41 kmph
Given:
Distance between Delhi to Bangalore = 1230 km
Difference between times for travelling by train and flight = 10 hrs.
Formula Used:
Speed = Distance/Time
Calculations:
Let the speed of train and flight be x kmph and y kmph respectively.
(1230/x) – (1230/y) = 10 ----(1)
When speed of train becomes thrice
(1230/y) – (1230/3x) = 10 ----(2)
Adding (1) and (2), we get
⇒ (1230/x) – (1230/3x) = 20
⇒ 1230 × (2/3x) = 20
⇒ x = 1230 × (2/3) × (1/20)
⇒ x = 41 kmph
∴ The speed of train is 41 kmph.