SOLUTION: A cyclist rode the first 30 mile portion of his workout at a constant speed. For the 20-mile cool down portion of his workout he reduced his speed by 5 miles per hour. Each portion

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Question 956597: A cyclist rode the first 30 mile portion of his workout at a constant speed. For the 20-mile cool down portion of his workout he reduced his speed by 5 miles per hour. Each portion of the workout took the same time.Find the cyclists speed during the first portion and find his speed during the cool down portion.
Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
r=original speed; r-5mph=cool down speed
30mi/r=20mi/(r-5mph) cross multiply.
30r mi-150mi^2/hr=20r mi Subtract 30r mi from each side.
-150mi^2/hr=-10r mi Divide each side by -10 mi
15mph=r ANSWER 1: His original speed was 15 mph.
15mph-5mph=10mph ANSWER 2: His cool down speed was 10 mph
CHECK
30mi/15mph=20mi/10mph
2hrs=2hrs