What always comes into a house through the keyhole?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

I cannot talk, but I always reply when spoken to. What am I?

With the help clues provided in the image, can you find the 5 digit key?

What came first, the chicken or the egg?

Find the next number in the series below.

6 18 270 72090 ?

Which famous Hollywood movie name is hidden in the below rebus?

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

A river should be crossed by a father, a mother and their two sons and two daughters.
There are some rules that should be followed while crossing the river. There can be only two people in the raft while crossing. The daughters cannot be with their father unless there is the presence of the mother. The sons cannot be with their mothers unless the father is present. Unless the guard is on the board, the criminals cannot be with any of the family members. Only the adults like the father, the guard, and the mother knows to use the raft.

How will they cross the river?

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?