Question 1

Two trains are moving towards each other on parallel tracks. Train A travels at 60 km/h and Train B travels at 40 km/h. If they are initially 500 km apart, in how many hours will they meet?

Accepted Answer

Step 1: When two objects move towards each other, their relative speed is the sum of their individual speeds. Step 2: Relative speed = 60 + 40 = 100 km/h. Step 3: Time = Distance ÷ Relative speed = 500 ÷ 100 = 5 hours.

Question 2

A car is chasing a bike on the same road. The car travels at 80 km/h and the bike travels at 50 km/h. If the bike is 90 km ahead, how long will it take for the car to catch the bike?

Accepted Answer

Step 1: When one object chases another in the same direction, relative speed = difference of speeds. Step 2: Relative speed = 80 - 50 = 30 km/h. Step 3: Time = Distance ÷ Relative speed = 90 ÷ 30 = 3 hours.

Question 3

Two cyclists start from the same point and travel in opposite directions. Cyclist P travels at 15 km/h and Cyclist Q travels at 25 km/h. After how many hours will they be 160 km apart?

Accepted Answer

Step 1: When two objects move in opposite directions from the same point, their relative speed is the sum of their speeds. Step 2: Relative speed = 15 + 25 = 40 km/h. Step 3: Time = Distance ÷ Relative speed = 160 ÷ 40 = 4 hours.

Question 4

Two runners start a race from the same point. Runner X runs at 12 m/s and Runner Y runs at 8 m/s in the same direction. How many seconds will it take for Runner X to be 100 metres ahead of Runner Y?

Accepted Answer

Step 1: Relative speed = 12 - 8 = 4 m/s (since they run in the same direction). Step 2: Time = Distance ÷ Relative speed = 100 ÷ 4 = 25 seconds.

Question 5

A boat travels upstream at 12 km/h and downstream at 20 km/h. What is the speed of the boat in still water?

Accepted Answer

Step 1: Let the speed of the boat in still water be B and the speed of the current be C. Step 2: Downstream speed = B + C = 20. Upstream speed = B - C = 12. Step 3: Adding both equations: 2B = 32, so B = 16 km/h.

Question 6

A man walks at 4 km/h and a woman walks at 6 km/h. They start from the same point and walk in the same direction. After 2 hours, how far apart will they be?

Accepted Answer

Step 1: Relative speed = 6 - 4 = 2 km/h (since they walk in the same direction). Step 2: Distance = Relative speed × Time = 2 × 2 = 4 km.

Question 7

A boat travels 120 km downstream in 4 hours and the same distance upstream in 6 hours. What is the speed of the boat in still water?

Accepted Answer

Step 1: Downstream speed = 120 ÷ 4 = 30 km/h. Upstream speed = 120 ÷ 6 = 20 km/h. Step 2: Speed of boat in still water = (Downstream speed + Upstream speed) ÷ 2 = (30 + 20) ÷ 2 = 25 km/h. Therefore, the boat's speed in still water is 25 km/h.

Question 8

Two runners start from the same point and run in the same direction. Runner A runs at 12 km/h and Runner B runs at 8 km/h. After how many hours will Runner A be 20 km ahead of Runner B?

Accepted Answer

Step 1: When both run in the same direction, relative speed = Speed of A - Speed of B = 12 - 8 = 4 km/h. Step 2: Runner A gains 4 km every hour. To gain 20 km, time required = 20 ÷ 4 = 5 hours. Therefore, Runner A will be 20 km ahead after 5 hours.

Question 9

A car and a motorcycle start from opposite ends of a 360 km highway and travel towards each other. The car travels at 80 km/h and the motorcycle at 70 km/h. At what distance from the car's starting point will they meet?

Accepted Answer

Step 1: Relative speed = 80 + 70 = 150 km/h (moving towards each other). Step 2: Time to meet = 360 ÷ 150 = 2.4 hours. Step 3: Distance covered by car = 80 × 2.4 = 192 km. Therefore, they meet 192 km from the car's starting point.

Question 10

A train 240 metres long is travelling at 54 km/h. How long will it take to completely pass a stationary platform of length 360 metres?

Accepted Answer

Step 1: Convert speed: 54 km/h = 54 × (5/18) = 15 m/s. Step 2: Total distance to cover = Length of train + Length of platform = 240 + 360 = 600 metres. Step 3: Time = Distance ÷ Speed = 600 ÷ 15 = 40 seconds. Therefore, it takes 40 seconds to completely pass the platform.

Question 11

A man cycles at 15 km/h and reaches his destination 2 hours late. If he cycles at 20 km/h, he reaches 1 hour early. What is the distance to the destination?

Accepted Answer

Step 1: Let the distance be D km and the required time be T hours. At 15 km/h: D = 15(T + 2). At 20 km/h: D = 20(T - 1). Step 2: Equating both: 15(T + 2) = 20(T - 1) → 15T + 30 = 20T - 20 → 50 = 5T → T = 10 hours. Step 3: Distance = 20(10 - 1) = 20 × 9 = 180 km. Therefore, the distance is 180 km.

Question 12

A man rows a boat upstream for 3 hours and covers 18 km. He then rows downstream for 2 hours and covers 20 km. What is the speed of the current?

Accepted Answer

Step 1: Upstream speed = 18 ÷ 3 = 6 km/h. Step 2: Downstream speed = 20 ÷ 2 = 10 km/h. Step 3: Let boat speed = b and current speed = c. Then b - c = 6 and b + c = 10. Step 4: Adding both equations: 2b = 16, so b = 8 km/h. Step 5: Subtracting: 2c = 4, so c = 2 km/h.

Question 13

A train 150 m long travels at 72 km/h. Another train 100 m long travels at 54 km/h in the same direction on a parallel track. How long does it take for the first train to completely overtake the second train?

Accepted Answer

Step 1: Convert speeds to m/s: 72 km/h = 72 × (5/18) = 20 m/s; 54 km/h = 54 × (5/18) = 15 m/s. Step 2: Relative speed = 20 - 15 = 5 m/s. Step 3: Total distance to be covered = Length of train 1 + Length of train 2 = 150 + 100 = 250 m. Step 4: Time = Distance ÷ Relative speed = 250 ÷ 5 = 50 seconds.

Question 14

A boat takes 6 hours to travel 120 km downstream and 8 hours to travel 120 km upstream. If the boat's speed in still water remains constant, what is the speed of the current?

Accepted Answer

Step 1: Downstream speed = 120 ÷ 6 = 20 km/h. Step 2: Upstream speed = 120 ÷ 8 = 15 km/h. Step 3: Let boat speed = b and current speed = c. Then b + c = 20 and b - c = 15. Step 4: Adding: 2b = 35, so b = 17.5 km/h. Step 5: Subtracting: 2c = 5, so c = 2.5 km/h.

Question 15

A car and a motorcycle start from opposite ends of a 360 km highway. The car travels at 80 km/h and the motorcycle at 100 km/h. They meet at a point, and after meeting, the car takes 3 more hours to reach its destination while the motorcycle takes 2 more hours. What is the distance covered by the motorcycle before they meet?

Accepted Answer

Step 1: Let them meet after time t hours. Distance covered by car = 80t, distance covered by motorcycle = 100t. Step 2: After meeting, car covers 80 × 3 = 240 km in 3 hours, and motorcycle covers 100 × 2 = 200 km in 2 hours. Step 3: Total distance = 80t + 100t = 360, so 180t = 360, thus t = 2 hours. Step 4: Distance covered by motorcycle before meeting = 100 × 2 = 200 km.

Question 16

Two trains start simultaneously from stations A and B, which are 480 km apart. Train X travels from A towards B at 60 km/h, while Train Y travels from B towards A at 40 km/h. A bird flies back and forth between the two trains at a constant speed of 80 km/h, starting from Train X. What is the total distance covered by the bird before the two trains meet?

Accepted Answer

Step 1: Find the relative speed of the two trains approaching each other: 60 + 40 = 100 km/h. Step 2: Calculate time until trains meet: 480 ÷ 100 = 4.8 hours. Step 3: The bird flies continuously at 80 km/h for the entire duration. Distance covered by bird = 80 × 4.8 = 384 km.

SBI Clerk Relative Speed

SBI Clerk Relative Speed — Past Exam Questions

Relative Speed— Rules & Concept

Key Points to Remember

Exam-Specific Tips

60-Second Revision — Relative Speed