SOLUTION: A dirt biker must circle a 9-mile track twice. His average speed must be 45 mph. On his first lap, he averaged 36 mph. How fast must he travel on his second lap in order to qualify

Question 1081458: A dirt biker must circle a 9-mile track twice. His average speed must be 45 mph. On his first lap, he averaged 36 mph. How fast must he travel on his second lap in order to qualify?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
A dirt biker must circle a 9-mile track twice.
His average speed must be 45 mph. On his first lap, he averaged 36 mph.
How fast must he travel on his second lap in order to qualify?
:
Find the time required to average 45 mph for 18 mi
t = 18/45
t = .4 hrs
Find the time taken averaging 36 mph for 9 mi
t = 9/36
t = .25 hrs
Find the time left after 9 mi
.4 - .25 = .15 hrs
Find the speed required to travel 9 mi in .15 hrs
9/.15 = 60 mph on the final 9 mi
:
:
Check this by finding the times
9/36 = .25 hrs
9/60 = .15 hrs
---------------
18/45= .4 hrs
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