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

Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?

I am an odd number. Take away a letter and I become even. What number am I?

Joseph buys three kinds of chocolates for 100 rupees. The first one is priced at 5 rupees, second one at 3 rupees and third one at 0.5 rupees.

If he bought 100 chocolates in total, how many pieces do you think he bought each chocolate?

Find the value of "?" in the ball picture Riddle below:

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

Replace each alphabet with the number (1-9) to make the below equation correct.

AB * C = DE - F = GH / I

Can you find the ages of a son, father and grandfather based on the following facts?
The sum of the ages of grandfather, father and son is 140 years.
The age of the son in months is the same as the grandfather in years.
The age of the son in days is the same as the father in weeks.

0 0 0 = 6
1 1 1 = 6
2 2 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

You can use any mathematical symbols in the space provided to make all above algebraic expressions true.

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?