- 2019: A 100 m long train is moving with a velocity of 60 km/h. The time taken by the train to cross a man standing on the platform is:

(A) 10 s (B) 12 s (C) 15 s (D) 20 s

**Answer:**

(D)

**Explanation:**

Speed = 60 * 5/18 = 50/3 m/sec

Time taken = 100 * 3/50 = 6 sec

- 2018: A boat which can travel at 10 km/h in still water crosses a river of width 1 km along the shortest path in 15 minutes. The velocity of the river water in km/h is:

(A) 2 (B) 2.5 (C) 3 (D) 4

**Answer:**

(C)

**Explanation:**

Speed downstream = 10 + v = 10 + 4