SOLUTION: greg drove at a constant speed in a rainstorm for 252 miles. he took a break, and the rain stopped. he then drove 144 miles at a speed that was six miles per hour faster than his p

Question 1016791: greg drove at a constant speed in a rainstorm for 252 miles. he took a break, and the rain stopped. he then drove 144 miles at a speed that was six miles per hour faster than his previous speed. if he drove for 9 hours, find the cars speed for each part of the trip.
Found 2 solutions by josgarithmetic, josmiceli:
Answer by josgarithmetic(39617) (Show Source): You can put this solution on YOUR website!

r rate in rain r+5 rate not in rain RT=D model for uniform travel rate rule relating rate, time, distance rate time distance While Rain r 252 Rain No more r+6 144 Total 9 Fill-in the missing time data: rate time distance While Rain r 252/r 252 Rain No more r+6 144/(r+6) 144 Total 9

Form the time-sum equation , and solve this for r.

Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = his speed in mi/hr for
driving during rainstorm
Let = his time in hrs for
driving during rainstorm
-----------------------------
Equation for driving during rainstorm:
(1)
Equation for driving after rainstorm:
(2)
-----------------------------
(1)
and
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
Use quadratic equation

and

---------------
His speed during rainstorm was 42 mi/hr
His speed after rainstorm was 48 mi/hr
----------
check:
(1)
(1)
(1) hrs
-----------------
(2)
(2)
(2)
(2)
(2) hrs
OK
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