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Janene and emily plan to go on a marathon training run. emily arrives late, so janene starts running 16 minutes before emily. janene runs at an average rate of 9 minutes per mile, and emily runs at an average rate of 8 1/4 minutes per mile. assuming that both girls started at the same location and ran the same route, how many minutes will emily take to catch up to janene?

User Bamcclur
by
6.3k points

2 Answers

7 votes

Final answer:

Based on the given information, it will take Emily approximately 19.8125 minutes to catch up to Janene.

Step-by-step explanation:

To find out how many minutes it will take Emily to catch up to Janene, we need to determine the distance that Janene runs while Emily catches up. Since Janene starts running 16 minutes before Emily and runs at an average rate of 9 minutes per mile, Janene will have run 16/9 = 1.78 miles before Emily starts running.

Emily runs at an average rate of 8 1/4 minutes per mile. Let's assume it takes Emily two minutes to catch up to Janene. So, when Emily catches up, she would have run a distance equal to t/8 1/4 miles. Since Janene has already run 1.78 miles, the total distance both of them run when Emily catches up is t/8 1/4 + 1.78 miles.

We know that the distance covered by both of them is the same when Emily catches up, so we can equate the distances: t/8 1/4 + 1.78 = t/9

Simplifying the equation, we get: t/8.25 - t/9 = 1.78

Combining the fractions on the left side, we get: (9t - 8.25t)/9*8.25 = 1.78

Solving for t, we get: (0.75t)/9*8.25 = 1.78

Multiplying both sides of the equation by 9*8.25/0.75, we get: t = 1.78 * (9*8.25/0.75)

Using a calculator to evaluate the right side of the equation, we get: t ≈ 19.8125

Therefore, it will take Emily approximately 19.8125 minutes to catch up to Janene.

User Shiv Kumar Baghel
by
6.4k points
3 votes
We write the kinematic equations for each one.
We have then:
For Janene:
r = (9) * t
For Emily:
r = (8.25) * (t-16)
Equating both equations:
(9) * t = (8.25) * (t-16)
t (9-8.25) = - 132
t = -132 / (9-8.25)
t = -176
We observe that time is negative, which physically does not make sense.
This means that Emily does NOT reach Janene.
Answer:
Emily DOES NOT reach Janene
User Armondo
by
6.2k points
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