Why do you find that most of the buildings are deprived of the 13th floor?

I am the fastest animal but cannot climb the tree. What am I?

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

How can you throw a ball as hard as you can and have it come back to you even if it doesn't hit anything there is nothing attached to it and no one else catches or throws it.

what one word does the below rebus identifies?

what's the probability of getting a king or a queen from a pack of 52 cards?

Find the next number in the series below

21 32 54 87 131 ?

The centre of the third figure is empty. What digit should fit inside?

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?

A boy collects white seashells from the sea and brings them home every night. When he has enough of them, he decides to sell them to a trader.

The trader is ready to buy the shells and he asks the boy about the quantity. At this, the boy starts calculating. He has a giant box that contains 3 mini boxes. Two of them have another mini box inside. If the giant box can hold 50 shells, how many brown shells can he sell to the trader?