What is the word or phrase?

In a concert, Christina is performing a dance show with her group.
At 10:00, she and her crew were dancing in an absolutely straight line. At that time Christina was standing in 4th position from both the front and back end of the row.

What was the size of her crew?

what does this picture(rebus) riddle 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?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

Here is what you have to do. You have to throw a ball as hard as you can but it must return back to you even if it does not bounce at anything. Also, you have nothing attached to the ball. There is no one on the other end to catch that ball and throw it back at you.

How will you do it?

John can place six large boxes or nine small boxes into a carton.

Can you find out in how many cartons can he place sixty-six boxes in total?

Can you find out the remainder when 3^300 is divided by 5?

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

Find the next number in the series below

21 32 54 87 131 ?