Numerical: Speed, Distance & Time MCQ — 15 Practice Questions with Answers

Explanation

When the train crosses a pole, it covers only its own length. Speed = 150 ÷ 10 = 15 m/s. While crossing the platform, the train covers train length + platform length in 25 seconds, so total covered distance = 15 × 25 = 375 m. Platform length = 375 − 150 = 225 m. Therefore the statement that the platform is 375 m long is incorrect; 375 m is the total distance covered, not the platform length.

Explanation

Use distance = speed × time. At 18 km/h, 20 minutes = 1/3 hour, so distance = 18 × 1/3 = 6 km. 40 minutes = 2/3 hour, so distance = 18 × 2/3 = 12 km. 1 hour 10 minutes = 70 minutes = 7/6 hour, so distance = 18 × 7/6 = 21 km. 1 hour 30 minutes = 1.5 hours, so distance = 18 × 1.5 = 27 km.

Explanation

First find the upstream speed from distance and time. Upstream speed = 60 ÷ 4 = 15 km/h. For a boat, upstream speed = speed in still water − speed of stream. Therefore, speed in still water = upstream speed + speed of stream = 15 + 3 = 18 km/h. The stream slows the boat while moving upstream, so its still-water speed must be higher than 15 km/h.

Explanation

For uniform motion, time = distance ÷ speed. Here the distance is 270 km and the speed is 54 km/h. So, time = 270 ÷ 54 hours. Since 54 × 5 = 270, the required time is 5 hours. No unit conversion is needed because distance is in kilometres and speed is already in kilometres per hour. Therefore, the bus completes the journey in 5 hours.

Explanation

Average speed for the whole journey is total distance divided by total time. The first 60 km at 40 km/h takes 60 ÷ 40 = 1.5 hours. The next 60 km at 60 km/h takes 60 ÷ 60 = 1 hour. Total distance = 120 km and total time = 2.5 hours. Therefore, average speed = 120 ÷ 2.5 = 48 km/h. The answer is not the simple average of 40 and 60.