<PRE><B>Question 1160242</B>
David and Andrew are traveling to a Mathematics conference. David travels 110 miles in 
the same time that Andrew travels 140 miles. Andrew travels 15 miles per hour faster 
than David. Find the average rate of each person.
======================================
d = r*t
The times are the same.
----------------
t = d/r
t = 110/r = 140/(r+15)
---
Cross multiply
110(r+15) = 140r
110r + 1650 = 140r
1650 = 30r
r = 55
etc</PRE>