A boat can row 12 km/h in still water. If the current marks 3 km/h, find the distance covered downstream by the boat in exactly 40 minutes. MCQ with Answer and Explanation

Explanation:
Speed of B = 400 / 50 = 8 m/s. Distance covered by B when A crosses the finish line at 45 seconds = 8 * 45 = 360 meters. Winning margin = 400 - 360 = 40 meters.

Explanation:
Let stream speed be c. Upstream speed = 15 - c, Downstream speed = 15 + c. Given: 2 * (15 - c) = 15 + c => 30 - 2c = 15 + c => 3c = 15 => c = 5 km/h.

Explanation:
Speed = 72 * (5/18) = 20 m/s. Length of train = Speed * Time = 20 * 10 = 200 meters.