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

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

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?

You are in a room that has three switches and a closed door. The switches control three light bulbs on the other side of the door. Once you open the door, you may never touch the switches again. How can you definitively tell which switch is connected to each of the light bulbs?

What happened when the wheel was invented?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

First, think of the colour of clouds. Next think the colour of snow. Last, think of the colour of the moon. Now, what do cows drink?

A beggar on the street can make one cigarette out of every 6 cigarette butts he finds. After one whole day of searching and checking public ashtrays the beggar finds a total of 72 cigarette butts. How many cigarettes can he make and smoke from the butts he found?

What's the next in the series?

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

On the dull night when the blonde was dozing, she heard an odd clamour and she saw that there was a bizarre man with a gun simply outside her home. So she raced to the telephone to call the police, however, she can't dial 911. Why?

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?