Sam Loyd's Trolley Puzzle

The Puzzle:

Sam Loyd's Trolley Puzzle
Charley Smalleash treats his best girl to a trolley ride, but on account of his limited resources they plan to walk back, so, if the car goes at the rate of nine miles an hour and they can walk at the rate of three miles an hour, how far could they ride if they must be back in eight hours?



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