SOLUTION: Noel is determined to get some excercise and walks to the store at a brisk rate of 4.5 mph. She meets her friend Dani at the store, and together they walk back at a slower rate of

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Question 182006: Noel is determined to get some excercise and walks to the store at a brisk rate of 4.5 mph. She meets her friend Dani at the store, and together they walk back at a slower rate of 3mph. Noel's total walking time was 1hr. How long did it take her to walk to the store? What is the distance to the store?
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
You can use the formula: d = rt where d = distance, r = rate (speed), and t = time.
For the trip to the store d%5B1%5D, the rate (speed) is 4.5 mph so we can write:
1) d%5B1%5D+=+4.5%28t%5B1%5D%29
For the return trip d%5B2%5D at 3 mph, we can write:
2) d%5B2%5D+=+3%28t%5B2%5D%29
Now since the distance to the store is the same as the return distance, you can write:
d%5B1%5D+=+d%5B2%5D and, since the total time for the trip was 1 hour, then:
t%5B1%5D+%2B+t%5B2%5D+=+1 Now we can rewrite this as: t%5B2%5D+=+1-t%5B1%5D and substitute it for the t%5B2%5D in equation 2) after setting equation 1) equal to equation 2).
4.5%28t%5B1%5D%29+=+3%28t%5B2%5D%29 Substitute t%5B2%5D+=+1-t%5B1%5D
4.5%28t%5B1%5D%29+=+3%281-t%5B1%5D%29 Simplify and solve for t%5B1%5D
4.5%28t%5B1%5D%29+=+3-3%28t%5B1%5D%29 Add 3%28t%5B1%5D%29 to both sides.
7.5%28t%5B1%5D%29+=+3 Divide both sides by 7.5
highlight%28t%5B1%5D+=+0.4%29hours.
So it took Noel 0.4 hours or 24 minutes to walk to the store.
To find the distance to the store (d%5B1%5D), substitute t%5B1%5D+=+0.4 into either equation 1) or equation 2) and solve for the distance.
d%5B1%5D+=+4.5%28t%5B1%5D%29 Substitute t%5B1%5D+=+0.4%29
d%5B1%5D+=+4.5%280.4%29
highlight%28d%5B1%5D+=+1.8%29miles.
Noel walked 1.8 miles to the store.