If 1+9+8=1, what is 2+8+9?

If you toss a coin 10 times and it lands heads up every time, what are the chances it will land heads up if you toss it again?

What is the next number in this series?

4,12,84,3612....

There is a shop where written:
Buy 1 for $1
10 for $2
100 for $3
I needed 999 and still only paid $3. How could this be financially viable for the shop-keeper?

Whats the next number in the below number sequence pattern.

Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

Complete the series by replacing "?" with the correct number.

ST ND RD TH '?'

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

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?

For an extra income, John decided to work at a Hotel for one hour daily. The manager offers him that they will pay him $11 after every 11 days.
However, John offered a different proposition to the manager. The offers stand as:
He will be paid just a penny on his first day.
Two pence will be paid on the second day,
Four pence will be paid on the third day.
And so on till the 11th day.

Should the Hotel manager accept his offer?