SOLUTION: In a walkathon to raise money for charity, elisa walked a certian distance at 5 mi/h and then walked twice that distance at 8 mi/h. Her total time walking and jogging was 2h and 15

Question 97986This question is from textbook
: In a walkathon to raise money for charity, elisa walked a certian distance at 5 mi/h and then walked twice that distance at 8 mi/h. Her total time walking and jogging was 2h and 15min. How many miles long was the walkathon?
I know that you have to multiply the time times the rate, but I can't figure out the equation to do it. Please help. This question is from textbook

Answer by ptaylor(2198) (Show Source): You can put this solution on YOUR website!
Distance(d) equals Rate(r) times Time(t) or d=rt; r=d/t and t=d/r
Let d=distance that Elisa walked at 5 mi/hr
Then 2d=distance she walked at 8 mi/hr
We know that the distance she walked at 5 mi/hr (d) plus the distance she walked at 8 mi/hr (2d) equals length of walkathon or 3d=length of walkathon
Now we are told that the time walked at 5 mi/hr (d/5) plus the time walked at 8 mi/hr (2d/8) equals 2.25 hr.
So our equation to solve is:
d/5+2d/8=2.25 multiply each term by 40 (the LCM)
8d+10d=90 combine like terms
18d=90 divide both sides by 18
d=5 mi------------------distance Elisa walked at 5 mi/hr
2d=2*5=10 mi------------------distance she walked at 8 mi/hr
3d=3*5=15 mi-----------length of walkathon
CK
5/5+10/8=2.25
1+1.25=2.25
2.25=2.25
Hope thsi helps----ptaylor

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