Question

A sprinter runs 100 meters at a speed of 7 meters per second. Then she cools down by running 100 meters at 3.5 meters per second. What is the best prediction?

Answer 1

To determine the best prediction of the sprinter's total time for the two segments of her run, we can calculate the time taken for each segment separately and then add them together.

1. **Time for the first segment (100 meters at 7 meters/second)**:

\[
\text{Time} = \frac{\text{Distance}}{\text{Speed}} = \frac{100 \text{ meters}}{7 \text{ meters/second}} \approx 14.29 \text{ seconds}
\]

2. **Time for the second segment (100 meters at 3.5 meters/second)**:

\[
\text{Time} = \frac{100 \text{ meters}}{3.5 \text{ meters/second}} \approx 28.57 \text{ seconds}
\]

3. **Total time**:

\[
\text{Total Time} = 14.29 \text{ seconds} + 28.57 \text{ seconds} \approx 42.86 \text{ seconds}
\]

Thus, the best prediction for the total time taken by the sprinter for both segments is approximately **42.86 seconds**.