Question 780035
Hi I don't understand how to set up this problem. During the first 20 mi of a 50 mi bicycle race, Roger's average speed was 16 mi/h. What must his average speed be during the remainder of the race if he is to finish the race in less than 2.5h?
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let x= Roger's average speed during remainder of the race
travel time=distance/speed
{{{20/16+30/x=2.5}}}
{{{5/4+30/x=2.5}}}
LCD:4x
5x+120=10x
5x=120
x=24
Roger's average speed during remainder of the race=24 mph