Question 1163732: Allison drove home at 62 mph, but her brother Austin , who left at the same time , could drive at only 42 mph. When Allison arrived , Austin still had 40 miles to go, How fat did Allison drive ?
Found 3 solutions by ikleyn, ankor@dixie-net.com, greenestamps:
Answer by ikleyn(52782)   (Show Source):
You can put this solution on YOUR website! .
The distance equation is
62*t = 42*t + 40.
Left side is the distance traveled by Allison.
Right side is the sum of the distance traveled by Austin plus 40 miles.
Both distances, on the left and on the right, are the same.
Solve for t
62t - 42t = 40
20t = 40
t = 40/20 = 2 hours.
Allison drove 2*62 = 124 miles. ANSWER
Solved.
Answer by ankor@dixie-net.com(22740)  (Show Source):
You can put this solution on YOUR website! Allison drove home at 62 mph, but her brother Austin, who left at the same time , could drive at only 42 mph.
When Allison arrived , Austin still had 40 miles to go,
How far did Allison drive ?
:
let d = distance A drove (home)
time = d/speed
:
 = 
cross multiply
62(d-40) = 42d
62d - 2480 = 42d
62d - 42d = 2480
20d = 2480
d = 2480
d = 124 mi the dist A drove home
Answer by greenestamps(13200)  (Show Source):
You can put this solution on YOUR website!
An informal solution -- which is nearly identical to the formal algebraic solution provided by tutor @ikleyn.
(Solving a problem informally -- by THINKING your way through the problem logically -- can be good mental exercise.)
The difference in the two speeds was 20mph;
the difference in the distances was 40 miles;
therefore, the amount of time was 2 hours;
therefore, the distance Allison drove was 62*2 = 124 miles.
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