Jan 30, 2024
Time for the new puzzler.
This is about my old neighbor, Frank.
Some years ago, back in the 1990s, Frank had to rent a car for some event. Some thing for work he had to do. And he knew that he had to drive it a considerable distance.
And he realized that he couldn't afford to pay for the rental fee and the mileage...
He couldn't figure out how to reach under the dash to disconnect the odometer...
So, he rented the car and figured he would just think of a way to get out of it. He had to figure out how to use the car a whole bunch, but then return it with fewer miles than he actually drove so he wouldn't be charged a lot for it. He was kind of sneaky, Frank.
The car he rented was a front-wheel drive car. And he discovered that if he drove the car in reverse, the odometer went backwards... (This was a long time ago...)
So he couldn't just drive backwards. That didn't make any sense. So he figured out how to rig it. He does the calculations. He does all the arithmetic. His plan will remove 75 miles from the odometer. So he sets up the car to run like this real slow all night in his garage, to pull that 75 miles off the odometer. He jacks the car up, and he goes under the hood and sets the throttle and puts the car in reverse. And he leaves. He goes into the house for the night.
The next morning, he comes out to the garage, and what does he see? This is a multiple choice puzzler. What does he see?
A. Zero miles have come off the odometer
B. 75 miles have come off the odometer
C. 150 miles have come off the odometer
D. 427 miles have come off the odometer
What did Frank see that next morning?
Good luck.
Answer time.
So, this guy, Frank, wanted to return a rental car with less miles appearing on the odometer. He figures out that in this old car, the odometer goes backwards if he goes in reverse. (This would never happen these days...)
So, he does the math and jacks up the car, and puts it in reverse in his garage.
When he comes back, what does he find? His goal in his calculations was to take 75 miles off the odometer.
And what was the outcome? This was multiple choice, and these were the options.
A. Zero miles have come off the odometer
B. 75 miles have come off the odometer
C. 150 miles have come off the odometer
D. 427 miles have come off the odometer
The answer is any of these could be correct, except the last one. Now I should explain that most front wheel drive cars run the odometer and speedometer off one axle only, unlike rear wheel drive cars which used to run it off the tail end of the transmission. And it would make no difference if you jacked up the rear of the car, whether one wheel spun, or both wheels spun because the transmission was turning and that's what it was measuring.
And so, if he had a rear wheel drive car and he had done this he would have gotten exactly what he wanted. The 75 miles. But the fact of the matter is, if he jacked up the whole front end, if he was really lucky, and both front wheels turned at the same speed, which is unlikely, he would have actually wound up with the answer #2, 75 miles exactly.
More likely than not, one wheel spun and one wheel didn't, which was often the case because if you have axles that have different lengths, because of the action of the differential, one wheel will spin and one wheel will just sit there. And if that one wheel happening to be the side where the transmission pick up is, then it would be 150 miles because that one wheel is going to turn twice as fast.
And if it happens to be the other side, the wheel that is not picked up by the transmission, then the answer would be 0 miles.
Lots of details here. But the answer could be A, B or C. But it could not be D.
Tricky question.
