What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

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

O T T F F S S ?

What does a man do only once in his lifetime, but women do once a year after they are 29?

10 people came into a hotel with 9 rooms and each guest wanted his own room. The bellboy solved this problem.
He asked the tenth guest to wait for a little with the first guest in room number 1. So in the first room, there were two people. The bellboy took the third guest to room number 2, the fourth to number 3, ..., and the ninth guest to room number 8. Then he returned to room number 1 and took the tenth guest to room number 9, still vacant.
How can everybody have his own room?

Count the number of triangles in the picture below:

Can you name four days which start with the letter 'T'?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

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

What does this rebus means ?

PROG WORKRESS

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