SOLUTION: Jack and Jill went up the hill at a rate of 8 units per minute. They came tumbling down at a rate of 8 units per second. What was their average rate, in units per minute, for the r

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Question 900271: Jack and Jill went up the hill at a rate of 8 units per minute. They came tumbling down at a rate of 8 units per second. What was their average rate, in units per minute, for the round trip?
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
_________________speed(u/min)_________time_______distance
UP________________8___________________d/8_____________d
DOWN______________60*8________________d/480___________d
Totals______________________________d/8+d/480________2d

The average speed for their round trip was the distance divided by time; using the totals.

Average speed, %282d%29%2F%28d%2F8%2Bd%2F480%29
2%2F%281%2F8%2B1%2F480%29

2%2F%2860%2F480%2B1%2F480%29

2%2F%2861%2F480%29

2%2A480%2F61

960%2F61

15%2645%2F61, close enough to about 15.75 units per minute