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

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

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 ?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

A 52% bias toss for head using the 51% tail bias coin was done to obtain a fair result.

Can you find how bias is the floor in this case?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

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

All of Jacob's shoes are red except two.
All of Jacob's shoes are green except two.
All of Jacob's shoes are yellow except two.

How many shoes does Jacob have?

I am working in a bus company. The company recently went under expansion and therefore there was not enough room for all the buses. As a result, twelve buses had to be stored outside.

If the company decides to expand the garage space by forty percent, enough space to accommodate the current buses will be created leaving enough space for twelve more buses if the need arises in future.

Can you calculate the number of buses that the company owns at present?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10