Train A takes 45 minutes more than train B to travel a distance of 450 km. Due to engine trouble speed of train B falls by a quarter, so it…

If Speed reduce by quarter, i.e, reduces by ¼th, then time should increase by ⅓rd if distance is constant.

=> If original time taken by Train B is T, then

⅓T = 75

=> T = 225 minutes.

=> Time taken by A = 225 + 45 = 270 minutes.

=> Speed of Train A = 450/270 x 60 = 100 kmph

So the option (3) is correct