Question

Jamal can run 1 mile in 5.05 minutes. If Jamal maintains this pace during a 5-kilometer (5K) race, he expects to break the course record of 15.25 minutes. Is Jamal's expectation reasonable? Explain.

Answer 1

Explanation:

Answer 2

The expectation is reasonable

Explanation:

Since Jamal runs 1 mile in 5.05 minutes, and expected to run 5 km in 15.25 minutes, we need to find if this is true. So, we need to find if he can actually run 5 km in 15.25 minutes.

Now 1 mile = 1609 m and 5 km = 5000 m. So, 5 km = 5000 m × 1mile/1609 m

5 km = 5000/1609 mile

Also since Jamal runs 1 mile in 5.05 minutes, the time it takes to run 5 km = 5000/1609 mile is 5000/1609 mile × 5.05 minutes/1 mile = 25,250/1609 minutes = 15.69 minutes.

Since our calculation shows that Jamal runs a 5 kilometer race in 15.69 minutes, the expectation that he will break the record in 15.25 minutes is reasonable. He can only break the record if he runs faster since there is a difference of 15.69 - 15.25 minutes = 0.44 minutes = 0.44 × 60 = 26.4 seconds which is quite a short time. So the expectation is reasonable.