There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

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

O T T F F S S ?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

I add 5 to 9 and get 2. The answer is correct, so what am I?

A horse was tied to a rope 5 meters long and the horses food was 15 meters away from the horse. How did the horse reach the food?

Can you solve this picture maths equation?

What can you see in the middle of March and April that you can never see in any other month?

You are an expert on paranormal activity and have been hired to locate a spirit haunting an old resort hotel. Strong signs indicate that the spirit lies behind one of four doors. The inscriptions on each door read as follows:

Door A: It's behind B or C
Door B: Its behind A or D
Door C: It's in here
Door D: It's not in here

Your psychic powers have told you three of the inscriptions are false, and one is true. Behind which door will you find the spirit?

The current time can be represented by below textual rebus.

0
=========
B.Sc
LLB

Can you tell us the current time?

How many times can you subtract the number two from the number fifty?