Question 248851
Diana's average driving speed is 8 miles per hour faster than Damon's. In the same lenth of time it takes Diana to drive 432 miles, Damon only drives 368 miles. for how long did diana and Damon each drive? 
.
You need to apply the "distance formula":
d = rt
where
d is distance
r is rate or speed
t is time
.
Let x = speed of Damon
then 
x+8 = speed of Diana
.
Let t = time driven
then
tx = 368  (equation 1 -- Damon)
t(x+8) = 432  (equation 2 -- Diana)
.
Solve equation 1 for x:
tx = 368
x = 368/t
Substitute the above into equation 2:
t(x+8) = 432
t(368/t+8) = 432
368 + 8t = 432
8t = 64
t = 8 hours