Question 639162
Richard's average driving speed is 3 miles per hour faster than grace's.
 In the same length it takes Richard to drive 180 miles, Grace only drives
 168 miles.
 What is Richard's average driving speed?
:
let s = Grace's driving speed
then
(s+3) = Richard's speed
:
Write a time equation; time = dist/speed
:
R's travel time = G's travel time
{{{180/(s+3)}}} = {{{168/s}}}
Cross multiply, solve for s