Level 1
Time, Distance & Speed MCQs set 2 for Join Pak Navy: Initial Academic Test Mathematics — 20 solved questions.
Q1. The town C is there is between A and B. If Nasir travels from A to C with a speed of 4km/h and from C to B with 6km/hr, what is the average speed of Nasir from A to B?
Answer: 4.8 km/h
Explanation: When equal distances are covered at different speeds, average speed = 2uv/(u+v) = 2×4×6/(4+6) = 4.8 km/h.
Q2. The diameter of a car's wheel is 48 cm. If the car travels at an average speed of 35 km/h, what is the approximate number of revolutions made by the wheel per minute?
Answer: 387
Explanation: Circumference of wheel = π × 0.48 m. Speed = 35 km/h = 35000/60 m/min. Revolutions/min = 35000/(60 × π × 0.48) ≈ 387.
Q3. A man swims downstream 72 km and upstream 45 km taking 9 hours each time; what is the speed of the current?
Answer: 1.5 kmph
Explanation: Downstream speed = 72/9 = 8 kmph; upstream speed = 45/9 = 5 kmph; current speed = (8 − 5)/2 = 1.5 kmph.
Q4. A train 100 meters long completely passes a man walking in the same direction at 6km/h in 5 second and a car in the same direction in 6 seconds. The speed of car is:
Answer: 18km/h
Explanation: Train's absolute speed = 20 m/s + 6 km/h = 21.67 m/s = 78 km/h; relative to the car the train covers 100 m in 6 s (16.67 m/s = 60 km/h), so car speed = 78 − 60 = 18 km/h.
Q5. A train 800 meters long is running at the speed of 78 km/h . If it crosses a tunnel in 1 minute, then the length of the tunnel (in meters) is:
Answer: 500 m
Explanation: Train speed = 78 km/h = 1300 m/min. In 1 minute, it covers 1300 m. Length of tunnel = 1300 − 800 = 500 m.
Q6. In a river, a man takes 3 hours in rowing 3 km upstream or 15 km downstream. What is the speed of the current?
Answer: 2km/hr
Explanation: Upstream speed = 3/3 = 1 km/hr; downstream speed = 15/3 = 5 km/hr. Current speed = (5−1)/2 = 2 km/hr.
Q7. A boat is rowed downstream at 15.5km/hr and upstream at 8.5 km/hr. The speed of the stream is________?
Answer: 3.5km/hr
Explanation: Stream speed = (downstream − upstream) / 2 = (15.5 − 8.5) / 2 = 3.5 km/hr.
Q8. A train 100 meters long takes 6 seconds to cross a man walking at 5 km/h in a direction opposite to that of the train. Find the speed of the train. Time, Speed, and Distance
Answer: 55 km/h
Explanation: The train and man move in opposite directions, so relative speed = train speed + 5 km/h. Crossing 100 m in 6 s gives relative speed = 60 km/h, so train speed = 60 − 5 = 55 km/h.
Q9. A train travels 16 km in 20 minutes. What is the speed of the train in km/h?
Answer: 48 km/h
Explanation: Speed = 16 km ÷ (20/60) hr = 16 × 3 = 48 km/h.
Q10. Two trains are running in opposite directions at speeds of 62 km/h and 40 km/h respectively. If the length of one train is 260 m, and they cross each other in 18 seconds, what is the length of the other train?
Answer: 250 meters
Explanation: The correct value is 250 meters. Apply the formula or arithmetic step shown in the question and
Q11. A train travelling at 36km/h took 10 seconds to pass a stationary man. What was the length of the train?
Answer: 100m
Explanation: 36 km/h = 10 m/s; length of train = speed × time = 10 × 10 = 100 m.
Q12. A man covered a certain distance at some speed. If he had moved 3 kmph faster, he would have taken 40 minutes less. If he had moved 2 kmph slower, he would have taken 40 minutes more. What is the the distance in km?
Answer: 40
Explanation: Setting up two equations from the speed-change conditions gives v = 12 km/hr and t = 10/3 hr. Distance = 12 × 10/3 = 40 km.
Q13. A boat goes 100 km downstream in 10 hours, and 75 Km upstream in 15 hours. The speed of the stream is________?
Answer: 2 (1/2) km/h
Explanation: Downstream speed = 100/10 = 10 km/h; upstream speed = 75/15 = 5 km/h. Stream speed = (10−5)/2 = 2.5 km/h.
Q14. A train moves past a telegraph post and a bridge 264 m long in 8 seconds and 20 seconds respectively. What is the speed of the train?
Answer: 79.2 km/hr
Explanation: Let train length = L; L/8 = (L+264)/20 gives L = 176 m; speed = 22 m/s = 79.2 km/hr.
Q15. A man can row upstream at 8 kmph and downstream at 13 kmph. The speed of the stream is?
Answer: 2.5 kmph
Explanation: Speed of stream = (downstream − upstream) / 2 = (13 − 8) / 2 = 2.5 kmph.
Q16. A train covers a distance of 10 km in 12 minutes. If its speed is decreased by 5 km /hr, the time taken by it to cover the same distance will be :__________?
Answer: 13 min 20 sec
Explanation: Original speed = 50 km/hr; reduced speed = 45 km/hr. New time = 10/45 hr = 13 min 20 sec.
Q17. A boat travels upstream from B to A and downstream from A to B in 3 hours. If the speed of the boat in still water is 9km/hr and the speed of the current is 3km/hr, the distance A and B is:_______?
Answer: 12 km
Explanation: Upstream speed = 9−3 = 6 km/h; downstream speed = 12 km/h. Total time: d/12 + d/6 = 3 → d = 12 km.
Q18. A man can row his boat with the stream at 6 km/h and against the stream in 4 km/h. The man's rate is________?
Answer: 5 kmph
Explanation: Speed in still water = (speed with stream + speed against stream) / 2 = (6 + 4) / 2 = 5 kmph.
Q19. A man swims downstream 30 km and upstream 18 km taking 3 hours each time, what is the speed of the man in still water?
Answer: 8 kmph
Explanation: Downstream speed = 30/3 = 10 km/h; upstream speed = 18/3 = 6 km/h. Speed in still water = (10+6)/2 = 8 km/h.
Q20. A boatman goes 2 km against the current of the stream in 1 hour and goes 1 km along the current in 10 minutes. How long will it take to go 5 km in stationary water?
Answer: 1 hr 15 min
Explanation: Upstream speed = 2 km/h; downstream = 1 km in 10 min = 6 km/h; still-water speed = (2+6)/2 = 4 km/h; time for 5 km = 5/4 h = 1 hour 15 minutes.