SOLUTION: During the first 20km of a 50 km bicycle race, Rosa's average speed was 30 km/h. What must her average speed be during the remainder of the race if she is to finish the race in les

Question 908918: During the first 20km of a 50 km bicycle race, Rosa's average speed was 30 km/h. What must her average speed be during the remainder of the race if she is to finish the race in less than 1.5 h?

Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
During the first 20km of a 50 km bicycle race, Rosa's average speed was 30 km/h. What must her average speed be during the remainder of the race if she is to finish the race in less than 1.5 h?
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travel time=distance/speed
let x=average speed during the remainder of the race
20/30+30/x=1.5
30/x=1.5-20/30
30/x=3/2-2/3=9/6-4/6=5/6
x/30=6/5
x=36
What must her average speed be during the remainder of the race? >36 km/hr
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