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Starting at home, Jessica traveled uphill to the toy store for 12 minutes at just 10 mph. She then traveled back home along the same path downhill at a speed of 30 mph. What is her average speed for the entire trip from home to the toy store and back?

User Llasram
by
8.2k points

2 Answers

3 votes

Answer:

the answer is 15

Completed by Jerome Maples Jr.

Explanation:

User Jellby
by
7.9k points
2 votes

Answer: 15 mph


Explanation:

Given: Time taken to travel uphill to the toy store= 12 minutes
=(12)/(60)=0.2\ hour

Let d be the distance(in miles) between the home and toy store.

Also,
Speed=(Distance)/(Time)


\\\Rightarrow10=(d)/(0.2)\\\Rightarrow\ d=0.2*10=2

Thus, distance from home to toy store= 2 miles

When she turn back, to home distance remains same.

The time taken by her to come back at 30 mph speed=


Time=(Distance)/(speed)=(2)/(30)=\ hour

Now, the average speed =
\frac{\text{Total distance}}{\text{Total time}}


=(2+2)/(0.2+(2)/(30))\\=(4)/((6+2)/(30))\\=(4*30)/(8)=(120)/(8)=15\ mph

User Jordan Rolph
by
8.2k points
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