SSC CGL (Prelims) General: Speed, Time and Distance questions with solutions

Q1. A car covers 240 m in 12 seconds. Find its speed.

1. 60 km/h
2. 72 km/h
3. 54 km/h
4. 48 km/h

Answer: 72 km/h

Speed in m/s = 240 ÷ 12 = 20 m/s. Converting to km/h: 20 × 18/5 = 72 km/h.

Q2. A person covers 12 km in 2 hours and returns the same distance in 3 hours. What is the average speed of the entire journey?

1. 4 km/h
2. 4.8 km/h
3. 5 km/h
4. 6 km/h

Answer: 4.8 km/h

The total distance is 12 + 12 = 24 km and the total time is 2 + 3 = 5 hours. Average speed = total distance / total time = 24/5 = 4.8 km/h.

Q3. A man walks at 4 km/h for 10 km and then at 5 km/h for 15 km. What is his average speed for the whole journey?

1. 4.8 km/h
2. 4.54 km/h
3. 5.1 km/h
4. 4.2 km/h

Answer: 4.54 km/h

Total distance = 10 + 15 = 25 km. Time taken = 10/4 + 15/5 = 2.5 + 3 = 5.5 hours. Average speed = 25/5.5 = 4.545... km/h, which is 4.54 km/h.

Q4. A man crosses a 150-metre-wide street in 30 seconds. His speed in km/h is:

1. 18 km/h
2. 15 km/h
3. 20 km/h
4. 12 km/h

Answer: 18 km/h

Speed = \(150/30 = 5\) m/s. Converting to km/h: \(5 \times 3.6 = 18\) km/h.

Q5. Suraj travels at a speed of 30 km/h. Find the distance covered by him in 72 seconds.

1. 650 m
2. 600 m
3. 450 m
4. 700 m

Answer: 600 m

Distance = speed × time. Convert 30 km/h to m/s: 30 × 5/18 = 25/3 m/s. Then distance in 72 s = (25/3) × 72 = 600 m.

Q6. A car covers three equal distances at speeds of 30 km/h, 45 km/h, and 90 km/h, respectively. What is the average speed of the car for the entire journey?

1. 50 km/h
2. 48 km/h
3. 60 km/h
4. 45 km/h

Answer: 45 km/h

When equal distances are covered at different speeds, average speed is total distance divided by total time. For speeds 30, 45, and 90 km/h, the average speed is $\frac{3}{\frac{1}{30}+\frac{1}{45}+\frac{1}{90}}=45$ km/h.