SOLUTION: Jenny walks 5 kilometers from her house to Star SuperMall to buy a new bike which she uses to return home. She averaged 10 kilometers faster on her bike than on foot. If her total

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Question 1041198: Jenny walks 5 kilometers from her house to Star SuperMall to buy a new bike which she uses to return home. She averaged 10 kilometers faster on her bike than on foot. If her total trip took 1 hour and 20 minutes, what is her walking speed in kph? Use the formula v = d/t .
Found 3 solutions by josgarithmetic, jorel555, MathTherapy:
Answer by josgarithmetic(39614) About Me  (Show Source):
You can put this solution on YOUR website!
system%28v=D%2FT%2CvT=D%29
          RATE          TIME          DISTANCE

WALK      v             %285%2Fv%29         5

BIKE      v+10           5%2F%28v%2B10%29     5

TOTAL                   1%261%2F3

Answer by jorel555(1290) About Me  (Show Source):
You can put this solution on YOUR website!
If v=d/t; then t=d/v. Since we know Jenny traveled 5 kilometers both ways; let n be her walking speed. So
5/n+5/(n+10)=4/3 hours
15/n+15/(n+10)=4
15(n+10)+15n=4(nē+10n)
30n+150=4nē+40n
4nē+10n-150=0
Using the quadratic formula, we get
n=5 or -7.5
So her speed on foot was 5 kmh, and on bike it was 15 kmh. ☺☺☺☺

Answer by MathTherapy(10549) About Me  (Show Source):
You can put this solution on YOUR website!

Jenny walks 5 kilometers from her house to Star SuperMall to buy a new bike which she uses to return home. She averaged 10 kilometers faster on her bike than on foot. If her total trip took 1 hour and 20 minutes, what is her walking speed in kph? Use the formula v = d/t.
With v as speed:
Time taken to walk to store: 5%2Fv
Time taken to ride home: 5%2F%28v+%2B+10%29
Since total time taken is matrix%281%2C2%2C+1%261%2F3%2C+hrs%29, we get the following TIME equation: 5%2Fv+%2B+5%2F%28v+%2B+10%29+=+1%261%2F3
5%2Fv+%2B+5%2F%28v+%2B+10%29+=+4%2F3
Solve for v, the walking speed. This should be 5 km/h