If 21x = 79x, what is the value of x?

John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

I’m tall when I’m young, and I’m short when I’m old. What am I?

In the given figure, you can see that four match sticks are used to form a square. Can you form five squares by using six matches?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

The Little ant seems to be always confused. Do you know why?

A deaf and mute man goes to the train station. Tickets for the train are 50 cents each. The man goes to the ticket booth and hands the man inside just a dollar. The man in the booth hands him two tickets.

How did the man in the booth know to give him two tickets without even looking at him?

What is the word or phrase below?
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