SOLUTION: Hi Arthur was riding his bike to school at 12km per hour. When he was 2/3 of the w ay he got a flat tyre. His dad drove him the rest of the way at 48km per hour. What was his av

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Question 1185060: Hi
Arthur was riding his bike to school at 12km per hour. When he was 2/3 of the w ay he got a flat tyre. His dad drove him the rest of the way at 48km per hour. What was his average speed.
Thanks


Found 3 solutions by JBnovelwriter, josgarithmetic, greenestamps:
Answer by JBnovelwriter(34)   (Show Source): You can put this solution on YOUR website!



24km/hr = avg speed
12km/hr = a third
12km/hr = a third
48km/hr = a third
3/3
add them together divide by 3 to get average
Answer by josgarithmetic(39613)   (Show Source): You can put this solution on YOUR website!
Two different distance lengths described. First part may be 2L and last part may be L. 
               SPEEDS        TIME            DISTANCES

part1           12           (2L)/12            2L

part2           48           L/48               L

TOTALS                     (2L)/12+L/48        3L

Question is to find average speed of the whole trip.













Answer by greenestamps(13195)   (Show Source): You can put this solution on YOUR website!


He rode twice as far on his bike, at a rate 1/4 the speed of the car. That means he spent 8 times as much time on his bike as in the car.

His average speed is then the weighted average of his two speeds:



ANSWER: 16km/hr
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