Question

A swimmer's best time in an event is 53.87 seconds. On average, his best time decreases by 0.28 second each of the next five times he swims the event. Does he accomplish his goal of swimming the event in less than 52.5 seconds?

Answer 1

Yes, the goal is accomplished.

Explanation:

A swimmer's best time is 53.87 seconds, decreasing by 0.28 seconds at each repetition of the event. You want to know if a goal of 52.5 seconds is met after 5 more repetitions.

Time

The event time can be modeled by ...

T = 53.87 -0.28n

where n is the number of times the event is run. After 5 times, the time will be ...

T = 53.87 -0.28·5 = 53.87 -1.40 = 52.47

The goal of a time less than 52.5 seconds will be met.