SOLUTION: A woman keeps fit by bcycling and runing everyday, monday she spends (1/5) hour at each activity, covering a total 7 miles. On tuesday she runs for 9 minutes and cycles for 21 minu

Question 528812: A woman keeps fit by bcycling and runing everyday, monday she spends (1/5) hour at each activity, covering a total 7 miles. On tuesday she runs for 9 minutes and cycles for 21 minutes, covering a total of 16.75 miles . Her running and cycling speeds dont change from day to day. what are the speeds at which she runs and cycles?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Write a distance equation for each day, dist = speed*time
b = biking speed
r = running speed
A woman keeps fit by bicycling and running everyday,
monday she spends (1/5) hour at each activity, covering a total 7 miles.
.2b + .2r = 7
Multiply by 5
b + r = 35
r = (35-b); use this for substitution
:
On tuesday she runs for 9 minutes and cycles for 21 minutes, covering a total of 16.75 miles
Change 9 min to hrs: 9/60 = .15 hrs running
Change 21min to hrs: 21/60 = .35 hrs biking
.35b + .15r = 16.75
Replace r with (35-b), find b
.35b + .15(35-b) = 16.75
.35b + 5.25 - .15b = 16.75
.35b - .15b = 16.75 - 5.25
.20b = 11.50
b =
b = 57.5 mph, obviously this problem has no reasonable solution
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