SOLUTION: on a trip of 600km, zoe drove part of the way at 80km/h and the remainder at 90km/h. if the total trip took 7 hours, how far did she drive at each rate

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Question 1140768: on a trip of 600km, zoe drove part of the way at 80km/h and the remainder at 90km/h. if the total trip took 7 hours, how far did she drive at each rate
Found 2 solutions by greenestamps, josgarithmetic:
Answer by greenestamps(13203) About Me  (Show Source):
You can put this solution on YOUR website!


Let x be the distance traveled at 80km/h; then (600-x) is the distance traveled at 90km/h.

The time spent at 80km/h is then x/80; the time spent at 90km/h is (600-x)/90.

The total time was 7 hours:

x%2F80%2B%28600-x%29%2F90+=+7

Solve using basic algebra....

Answer by josgarithmetic(39623) About Me  (Show Source):
You can put this solution on YOUR website!
                SPEED      TIME           DISTANCE
part1            80        (600-d)/80      600-d
part2            90        d/90              d
TOTAL                      7              600

%28600-d%29%2F80%2Bd%2F90=7
Solve for d and evaluate 600-d.