Find the value of "?" in the ball picture Riddle below:

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

A brand new Mobile Phone was on sale at 20% as a promotional offer. By what per cent must the Mobile price be increased to sell it at the original price again?

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?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

In the figure, you can see nine stars. What you have to do is connect all of them by using just four line and without lifting your hand i.e. in a continuous flow.

If Japan and Panama decided to merge into a single country, probably people will name it Japanama.

Can you think of two more such country's unions that could produce similar names like Japanama by overlapping their three letters?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

You see me once in June, twice in November, and not at all in May. What am I?

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?