SOLUTION: Bobby and Rick are in a 10 lap race on a one-mile track oval track. Bobby, averaging 90 mph, has completed two laps just as Rick is getting his car onto the track. What speed does

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Question 50640This question is from textbook College Algebra
: Bobby and Rick are in a 10 lap race on a one-mile track oval track. Bobby, averaging 90 mph, has completed two laps just as Rick is getting his car onto the track. What speed does Rick have to average to be even with Bobby at the end of the tenth lap?
Book Hint: Bobby does 8 miles in the same time as Rick does 20 miles.
Book Answer: 112.5 mph This question is from textbook College Algebra

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Bobby and Rick are in a 10 lap race on a one-mile track oval track. Bobby, averaging 90 mph, has completed two laps just as Rick is getting his car onto the track. What speed does Rick have to average to be even with Bobby at the end of the tenth lap?
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Bobby DATA:
rate=90 mph ; distance = 8 miles ; time= d/r=8/90 hrs.
Rick DATA:
rate=x mph ; distance = 10 miles ; time = d/r= 10/x
EQUATION:
time Rick = time Bobby
10/x= 8/90
x=900/8
x=112.5 mph (Rick's rate)
Cheers,
Stan H.