The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

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

When it's bad luck to meet a black cat?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

Before the start of the car race, John and Jacob have the same amount of fuel in their car. With this fuel, John can drive for 4 hours while Jacob can drive five hours.
After a time they realize that the amount of fuel left in John's car is 1/4th of the fuel in Jacob's.

For how long they are racing?

Every words stands for unique digit that makes the arithmetic equation true

SEVEN + SEVEN + SIX = TWENTY.

What are the digits ?

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

Replace the question mark in the picture below.

Can you name any English verb that becomes its past tense by simply rearranging the alphabets ?