<PRE><B>Question 956597</B>
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

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