Question

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?

Answer 1

the answer is 15

Completed by Jerome Maples Jr.

Explanation:

Answer 2

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`