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?

You bought me for dinner but never eat me. What am I?

What has many keys but can’t open a single lock?

Can you decipher these quotes by Albert Einstein?
Blf xzm mvevi hloev z kilyovn lm gsv ovevo lm dsrxs rg dzh xivzgvw.

The ages of a father and son add up to 66.
The father's age is the son's age reversed.
How old could they be?
(3 possible solutions).

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.

Can you replace the question mark with the correct number in the below table sequence?

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

What is the fastest way to double your money?

You can hear me, but you can't touch or see me.

What am I?