SOLUTION: A runner’s heart rate in beats per minute is given by the formula Heart rate = 65 + 53 / (4t + 1) where t is the number of minutes after the start of a cool-down period. Find the

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Question 304898: A runner’s heart rate in beats per minute is given by the formula Heart rate = 65 + 53 / (4t + 1) where t is the number of minutes after the start of a cool-down period. Find the runner’s heart rate in 10 minutes. When is the runner’s heart rate equal to 68 beats per minute?
I tried to substitute 10 for "t" because it said t represents the minutes. I tried to solve it like that but got a answer 4718/41. Could you please help me set this equation up so I can learn how to do it and how to get the answer. Thanks
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
A runner’s heart rate in beats per minute is given by the formula Heart rate = 65 + 53 / (4t + 1) where t is the number of minutes after the start of a cool-down period. Find the runner’s heart rate in 10 minutes.
:
H.R. = 65 + 53%2F%284%2810%29%2B1%29
H.R. = 65 + 53%2F41
H.R. = 65 + 1.3
H.R. = 66.3
:
When is the runner’s heart rate equal to 68 beats per minute?
65 + 53%2F%284t%2B1%29 = 68
Subtract 65 from both sides
53%2F%284t%2B1%29 = 68 - 65
53%2F%284t%2B1%29 = 3
Multiply both sides (4t+1)
53 = 3(4t+1)
53 = 12t + 3
53 - 3 = 12t
50 = 12t
t = 50%2F12
t = 4.2 minutes