SOLUTION: In a walk-a-thon to raise money for charity, Elisa walked a certain distance at 5 mph and then jogged twice that distance at 8 mph. Her total time walking and jogging was 2 hours

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Question 262893: In a walk-a-thon to raise money for charity, Elisa walked a certain distance at 5 mph and then jogged twice that distance at 8 mph. Her total time walking and jogging was 2 hours and 15 minutes. How far did Elisa get?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Elisa walked a certain distance at 5 mph and then jogged twice that distance at 8 mph.
Her total time walking and jogging was 2 hours and 15 minutes.
How far did Elisa get?
:
let d = her walking distance
then
2d = her jogging dist
and
3d = total distance
:
Change 2 hr 15 min to 2.25 hrs
:
Write a time equation: Time = dist/speed
:
Walk time + jog time = total time
d%2F5 + %282d%29%2F8 = 2.25
Multiply by 40, results:
8d + 5(2d) = 40(2.25)
8d + 10d = 90
18d = 90
d = 90%2F18
d = 5 mi, walking
then
3(5) = 15 mi total dist
;
:
Check, find the time
5/5 + 10/8 =
1 + 1.25 = 2.25