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

1 dollar = 100 cent
= 10 cent x 10 cent
= 1/10 dollar x 1/10 dollar
= 1/100 dollar
= 1 cent

=> 1 dollar = 1 cent

solve this tricky problem?

What has 13 hearts but no other organs?

I am the largest in my family of fifty.
The youngest of our family lives separately from the rest of the family and so do I.
I am regarded as harsh and tough.
I am so large, you cut me in two equal halves,
each half would still be larger than the second largest member of the family.
Who am I?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

Can you make the number 24 by utilizing the numbers 1, 3, 4 and 6? You must use one number only one time and you can use mathematical operation symbols anytime anywhere.

Steffi's daughter Jazelle needs to be picked up from school every day.
Steffi asks one of her colleagues to pick up Jazelle from the school. Steffi devised a password system to confirm that Jazelle goes with the correct colleague only.

The password on Monday was SJM16.
The password on Wednesday was TAW39.

What will the password be for Friday?

How can you drop a raw egg from a height onto a concrete floor without cracking it?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?