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