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

I am white when I am dirty, and black when I am clean. What am I?

What four weights can be used to balance from 1 to 30 pounds?

John gave half of the apples he had plus one more to Jacob. He gave half of the remaining ones plus one more to James. Now, John was left with just one apple.

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

In this image, you can see three almost identical Doraemon images. Can you spot the odd one out from them?

You can see it everyday, But cannot touch it at will. What is it?

Which is the smallest number that you can write using all the vowels exactly once?

Can you count the number of squares in the given picture?

Find three numbers such that

* When we multiply three numbers, we will get the prime numbers.
* The difference between the second and the first number is equal to the third and second.

People make me, save me, change me, raise me. What am I?