An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

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

An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

I am dry when I go inside, but wet when I am pulled outside.
The longer I am inside, the stronger I get
When I am completely out, I am wet and I literally sag
Who am I?

What demands an answer, but asks no questions

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

Can you solve the below tricky visual equation?

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

Find the missing letter in the last circle logically in the given below picture.