Question

Starting at home, Emily traveled uphill to the hardware store for 60 minutes at just 6 mph. She then traveled back home along the same path downhill at a speed of 12 mph. What is her average speed for the entire trip from home to the hardware store and back?

Answer 1

its 8 mph and its not 24 mph

Answer 2

8 mph

Explanation:

Emily traveled uphill to the hardware store for 60 (1 hour) minutes at just 6 mph.

`Distance = Speed * Time`

`Distance = 6 * 1`

`Distance = 6 m`

She then traveled back home along the same path downhill at a speed of 12 mph.

So, on returning she traveled the same distance of 6 m.

So, time taken on returning =
`(Distance)/(Speed)`

=
`(6)/(12)`

=
`(1)/(2)`

So, average Speed=
`(Total Distance)/(Total Time) =(6+6)/(1+(1)/(2))`

=
`=(12)/((3)/(2))`

=
`8`

Thus her average speed for the entire trip from home to the hardware store and back is 8 mph.