Thread: Helps solving rate problem

Problem: Ramona cycles from her house to school at 15 miles per hour. Upon arriving, she realizes that it is Saturday and immediately cycles at 25 miles per hour. If the entire round-trip takes her 32 minutes, then what is her average speed, in miles per hour, for the entire round-trip?

I set up a table:

Leg 1: R: 15 D: x
Leg 2:: R: 25 D: x
Total: D: 2x T: 32 minutes

I know that average speed = total distance/total time... I have total time, so I need total distance (2x). I'm not too sure what to do from here. I did x/15 + x/25 = 32 minutes.. (That didn't go anywhere). Thanks for the help.

r x t = d

going ... 15t = d

returning ... 25[(32/60) - t) = d

avg. speed = (total distance)/(total time) = (2d)/(32/60)

I got 18.75. Thanks!

Hello, benny92000!

Ramona cycles from her house to school at 15 mph. .Upon arriving, she realizes
that it is Saturday and immediately cycles home at 25 mph. .If the entire trip
takes her 32 minutes, what is her average speed for the entire trip?

Let = distance from home to school (in miles).

She went miles at 15 mph.
. . This took hours.

She went miles at 25 mph.
. . This took hours.

Her total time is 32 minutes

We have: .


She went miles in hours.

Her average speed was: .

Originally Posted by benny92000

Problem: Ramona cycles from her house to school at 15 miles per hour. Upon arriving, she realizes that it is Saturday and immediately cycles at 25 miles per hour. If the entire round-trip takes her 32 minutes, then what is her average speed, in miles per hour, for the entire round-trip?

I set up a table:

Leg 1: R: 15 D: x
Leg 2:: R: 25 D: x
Total: D: 2x T: 32 minutes

I know that average speed = total distance/total time... I have total time, so I need total distance (2x). I'm not too sure what to do from here. I did x/15 + x/25 = 32 minutes.. (That didn't go anywhere). Thanks for the help.

Hi benny92000,
Your equation d/15 +d/25 = total time was correct but you needed to change minutes to hours to get d=5miles