SOLUTION: During the first part of a trip, Stra travels 40 miles at a certain speed. Stra travels 100 miles on the second part of the trip at a speed 3 mph slower. The total time for the tri

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Question 886437: During the first part of a trip, Stra travels 40 miles at a certain speed. Stra travels 100 miles on the second part of the trip at a speed 3 mph slower. The total time for the trip is 2 hrs. What was the speed on each part of the trip?
Answer by josgarithmetic(39630) About Me  (Show Source):
You can put this solution on YOUR website!
r is the speed on the first part of the trip.

________________speed_______time_______distance
First Part_______r__________(___)_________40
Second Part_____r-3_________(___)________100
TOTAL________________________2

RT=D basic law about uniform rates of travel.
T=D/R.

________________speed_______time__________distance
First Part_________r__________40%2Fr____________40
Second Part_______r-3_________100%2F%28r-3%29________100
TOTAL________________________2

Solve for r in highlight_green%2840%2Fr%2B100%2F%28r-3%29=2%29.

Solving that should pass some steps simplifying to r%5E2-73r%2B60=0, and general solution should be highlight%28r=72%29 mph. The other part of the trip is highlight%28r-3=69%29 mph.