What does below rebus means ?

A mother bought three dress for her triplets daughters(one for each) and put the dresses in the dark. One by one the girls come and pick a dress.
What is the probability that no girl will choose her own dress?

There are forty elephants and they have forty-fore heads. How can this be possible?

Through your logical capabilities, can you make 7 an even?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

We have shown you a regular water barrel as below. Without using any measuring device can you check if the barrel is more than half-filled or less than half-filled?

What does this mathematical rebus means ?

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

In a university, a professor gave a set of three problems to the three brilliant students of his class. See the image for the questions.

An explorer goes on an exposition in the jungle. He sets up camp in the middle of the jungle. The next morning he sees something with a head and a tail, but he is not afraid. What did he see in his bag?