Braingle Lite



Tricky Substitution Equation

Category:Trick
Submitted By:eighsse
Fun:*** (2.43)
Difficulty:*** (2.78)



Karl and his friend Larry are always pulling trick brain teasers on each other. Larry has been getting the best of Karl all too often lately, so Karl really wants to get him back. He comes up with a good one, and writes the following on a piece of paper:
" YXZ
- YXY
= Y"
He shows it to Larry, and says, "Each different letter in this equation stands for a different digit. All instances of a given letter stand for the same digit. There are multiple true solutions, but what is the greatest digit that Y can stand for in a true solution?" Larry scans the equation over and over. He can't come up with any way that the answer could not be 4. "The answer must be four," he says, with confidence. Karl smiles and replies, "Sorry, you're incorrect."

What is the correct answer?

Show Hint Show Answer



Comments on this teaser


Posted by charlottes-odd12/17/13
Another good one eighsse! :)

Posted by eighsse12/17/13
Thanks charlotte :)

Posted by koin_era34512/20/13
I don't know if this should be in trick, but I like it nonetheless.

Posted by eighsse12/20/13
It's in Trick because at first sight, the X's will likely be considered letters, which must stand for digits. But they really are multiplication signs, not letters. The only other category I might consider it to be is Situation, as it's somewhat unfair to the solver, considering that the body of the teaser is typed with an actual letter "X" character. So it's written with a third-person perspective since an "X" and a multiplication sign, in writing, are generally interchangeable. This might make it more fit for Situation, but I still feel it is more of a Trick.

Posted by dalfamnest07/04/14
As a trick, I think it's great - top marks!! Thanks for something new and different. :D :D

Posted by eighsse07/04/14
Thanks dalfamnest, glad you enjoyed it :)

Posted by Zag2407/21/14
Nicely done. Of course, I can beat your solution with my own. No one said that the digits were DECIMAL digits. (Back in the old days, I used to have to add and subtract hexidecimal values all the time. But there's no reason these digits aren't in base 10000000.)

Posted by eighsse07/21/14
Hah! This is true. Very nice, zag.




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