Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

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Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

Which flower has two lips?

Who always enjoys poor health?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

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Would you want to play first or second?

PS: The sum should be exactly 15.

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Can you find out how many did he have in the beginning?