A train traveling at 60 km/h overtakes a motor cyclist riding at 12 km/h in the same direction in 12 seconds. Find the length of the train. MCQ with Answer and Explanation

Explanation:
Downstream speed = 10 + 2 = 12 km/h. Upstream speed = 10 - 2 = 8 km/h. Let distance be d. d / 12 + d / 8 = 2.5 => 5d / 24 = 2.5 => 5d = 60 => d = 12 km.

Explanation:
Distance is constant, so S1 * T1 = S2 * T2 => 45 * 40 = S2 * 30 => S2 = (45 * 40) / 30 = 60 km/h.

Explanation:
Let original speed be s. 200 / (s - 10) - 200 / s = 1 => 200(s - s + 10) = s(s - 10) => 2000 = s(s - 10). Solving s^2 - 10s - 2000 = 0 gives (s - 50)(s + 40) = 0. Since speed is positive, s = 50 km/h.