SOLUTION: Greg drove at a constant speed in a rainstorm for 273 miles. He took a&#8203; break, and the rain stopped He then drove 240 miles at a speed that was 9 miles per hour faster th

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Question 1036324:
Greg drove at a constant speed in a rainstorm for 273 miles. He took a break, and the rain stopped He then drove 240 miles at a speed that was 9 miles per hour faster than his previous speed. If he drove for 12 hours, find the car's speed for each part of the trip.
Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website!
Let = time in hrs for 1st part of trip
= his time in hrs for 2nd part of trip
Let = his speed in mi/hr for 1st part of trip
= his speed in mi/hr for 2nd part of trip
-------------------------------------------
Equation for 1st part:
(1)
Equation for 2nd part:
(2)
----------------------------
(1)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
----------------------------
Use quadratic formula

and

If I had used the negative square root of , then
time would be negative, which is not allowed
------------------------
The speed for 1st part is 39 mi/hr
The speed for the 2nd part is 48 mi/hr
---------------------------------
check:
(1)
(1)
(1) hrs
and
(2)
(2)
(2)
(2)
(2)
(2) hrs
OK

SOLUTION: Greg drove at a constant speed in a rainstorm for 273 miles. He took a&#8203; break, and the rain stopped He then drove 240 miles at a speed that was 9 miles per hour faster th

SOLUTION: Greg drove at a constant speed in a rainstorm for 273 miles. He took a break, and the rain stopped He then drove 240 miles at a speed that was 9 miles per hour faster th