Can you solve the tricky chess rebus puzzle below by ciphering the hidden meaning?

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

O T T F F S S ?

Can you fill the blank with the correct number?

6 30 870 756030 _____

Rearrange the letters in "new door" to make one word.

Can you find the ages of a son, father and grandfather based on the following facts?
The sum of the ages of grandfather, father and son is 140 years.
The age of the son in months is the same as the grandfather in years.
The age of the son in days is the same as the father in weeks.

The teacher told the student that if he told a lie then he will be expelled from school and if he told the truth then he still is expelled from school.

What can a student say to prevent his being expelled from school?

After a heavy Thanksgiving meal, the night watchman went to work. In the morning, he told his boss he had dreamed that a saboteur planted a bomb in the factory and that he felt it was a warning. The boss promptly fired him. Worker confused, Why boss fire him?

Jack have ten pairs of black socks, eight pairs of white socks and seven pairs of green socks. Everything is mixed in a draw. As there is no light he were not able to identify the colour of the socks. How many of the socks did he want to take to match one pair

Who is that with a neck and no head, two arms and no hands? What is it?

Can you solve the below tricky visual equation?