In a 300 metres race A beats B by 15 metres or 5 seconds. A's time over the course is-

Options

A. 100 seconds
B. 95 seconds
C. 105 seconds
D. 90 seconds

Answer

To solve the problem, we need to determine the time taken by A to complete the 300 meters race. We know that A beats B by 15 meters, which means when A finishes the race, B is still 15 meters behind. Additionally, we know that this difference corresponds to a time difference of 5 seconds.

### Step-by-Step Solution:

1. **Understanding the Problem**:
- A completes 300 meters while B only covers 285 meters (300 - 15) when A finishes.
- The time difference between A and B is 5 seconds.

2. **Finding B's Speed**:
- Since B covers 15 meters in 5 seconds, we can calculate B's speed.
- Speed of B = Distance / Time = 15 meters / 5 seconds = 3 meters/second.

3. **Calculating B's Time for 300 meters**:
- Now, we need to find out how long it takes B to cover 300 meters.
- Time taken by B to cover 300 meters = Distance / Speed = 300 meters / 3 meters/second = 100 seconds.

4. **Finding A's Time**:
- Since A beats B by 5 seconds, we can find A's time by subtracting the time difference from B's time.
- Time taken by A = Time taken by B - Time difference = 100 seconds - 5 seconds = 95 seconds.

5. **Conclusion**:
- Therefore, A's time over the course is **95 seconds**.

### Final Answer:
A's time over the course is **95 seconds**.