What does this Rebus Picture mean?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

A chicken farmer has figured out that a hen and a half can lay an egg and a half in a day and a half. How many hens does the farmer need to produce one dozen eggs in six days?

I make two people out of one. What am I?

John was driving a bus and got stuck when passing through an underpass. Then came Jacob with a needle and got the bus out of the underpass.

What did the boy do?

You have two jars of chocolates labelled as P and Q. If you move one chocolate from P to Q, the number of chocolates on B will become twice the number of chocolates in A. If you move one chocolate from Q to P, the number of chocolates in both the jars will become equal.

Can you find out how many chocolates are there in P and Q respectively?

A father's child, a mother's child, yet no one's son.

Who am I?

What happened when the wheel was invented?

In the four images below, can you find the odd one out?

What does below science rebus mean?

Ag Ag Ag
Ag SPOON Ag
Ag Ag Ag