PDA

View Full Version : Finding Driving Speeds


zqueez
Nov 12, 2008, 07:15 AM
A girl drove 300 miles from her hometown to Tucson. During her return trip, she was able to increase her speed by 11 mph. If her return trip took 1 hour less time, find her original speed and her speed returning home.

I just want to know how to set up this problem. The fact that her return took 1 hour less time is throwing me off.

Can someone help me?

Thank you.

ebaines
Nov 12, 2008, 08:21 AM
Using the basic equation that distance = velocity times time:

D = VT

On the way out she drove 300 miles at V MPH, and on the return she drove at V + 11 MPH. The time driving out is T, and the time driving back is T-1. So you have 2 equations in 2 unknowns:

300= VT
300 = (V+11)(T-1)

Can you take it from here?

zqueez
Nov 12, 2008, 08:43 AM
Thank you so much!