Question 1140768
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Let x be the distance traveled at 80km/h; then (600-x) is the distance traveled at 90km/h.<br>
The time spent at 80km/h is then x/80; the time spent at 90km/h is (600-x)/90.<br>
The total time was 7 hours:<br>
{{{x/80+(600-x)/90 = 7}}}<br>
Solve using basic algebra....