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

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

Solve below popular number sequence
314 159 265 358 979 323 846 ?

A man has eighty-one cows ( numbered 1,2,3...81 as such). The beauty is that cow no. 1 gives 1ltr of milk, cow no. 2 gives 2ltrs of milk and so on. The man wants to equally distribute the cows among his nine sons so that each one of them gets the same quantity of milk.

Get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?

Find three whole, positive numbers that have the same answer when multiplied together as when added together.

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

I have two coins.
* One of the coins is a faulty coin having a tail on both sides of it.
* The other coin is a perfect coin (heads on side and tail on other).

I blindfold myself and pick a coin and put the coin on the table. The face of the coin towards the sky is the tail.

What is the probability that another side is also tail?