SOLUTION: Matt took 7hrs to drive from Kingston to Montreal a total distance of 485 km. He drove most of the way at 100 km/h, but was slowed to 30 km/h during a trafic jam. How many hours he

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Question 1201192: Matt took 7hrs to drive from Kingston to Montreal a total distance of 485 km. He drove most of the way at 100 km/h, but was slowed to 30 km/h during a trafic jam. How many hours he spend driving at each speed?
D:distance
S:speed
T:time
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39626)   (Show Source): You can put this solution on YOUR website!




                 SPEED        TIME          DISTANCE
MOST WAY         100
TRAFF. JAM        30
Total                           7               485

You can do this! Assign ONE variable for either of the missing time quantities...
Answer by ikleyn(52858)   (Show Source): You can put this solution on YOUR website!
.
Matt took 7hrs to drive from Kingston to Montreal a total distance of 485 km.
He drove most of the way at 100 km/h, but was slowed to 30 km/h during a trafic jam.
How many hours he spend driving at each speed?
~~~~~~~~~~~~~~~ 

    t hours at the speed of 100 km/h, and 

(7-t) hours at the speed of 30 km/h.


Write the total distance equation

    100t + 30*(7-t) = 485  kilometers.


From this equation, find t.



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