SOLUTION: sam was driving to chicago his rate for the first 120 miles was 10 mph than his rate for the last 100 miles, of his entire trip took 4 hours,what was his speed on each part of the

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Question 1131101: sam was driving to chicago his rate for the first 120 miles was 10 mph than his rate for the last 100 miles, of his entire trip took 4 hours,what was his speed on each part of the trip
Answer by josgarithmetic(39616) About Me  (Show Source):
You can put this solution on YOUR website!
10 mph MORE or LESS? Which is missing? 
If first part of trip 10 mph more than second part, then:

              SPEED        TIME          DISTANCE

first part      r+10       120/(r+10)      120

last part        r         100/r           100

TOTAL                        4

120%2F%28r%2B10%29%2B100%2Fr=4


If instead the description is that the 120 miles was done at 10 mph LESS than the last 100, then this equation:
120%2F%28r-10%29%2B100%2Fr=4