# Math

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Runner runs 8 miles at 5 miles per hour, then another 2 miles at 7 miles per hour, find average speed.

• Math -

Average speed = total distance/total time

time for first leg = 8/5 hrs
time for 2nd leg = 2/7 hours
total time = 8/5 + 2/7 or 66/35

avg speed = 10/(66/35) = 10(35/66) = 5.3 mph

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