What's the next in the series?

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

Count the Triangle in the figure given below:

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?

Can you find the dog hidden in a group of pandas?

There was a man he lives in a hotel each morning he presses the first floor button each evening if there is a person in the elevator he asks him to press the 10 floor button if there is no one in the elevator he takes the stairs why.

Eight of us go fourth, not back, to protect our king from an attack. What are we?

A tourist visits a small town for his research. While in the town, he decides to get a haircut. Since the town is quite small, there are only two barbers in the town � one on the North Street and one on the South Street. The barbershop on the North Street is a mess and the barber has a weird and pathetic haircut. While the barbershop at the South Street is pretty tidy and the barber as well has an impressive haircut.

Which barbershop will the tourist visit for his haircut and why?

What is the next number in the series?

15 29 56 108 208 ?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?