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

Replace each alphabet with the number (1-9) to make the below equation correct.

AB * C = DE - F = GH / I

What has many keys but can’t open a single lock?

A word I know has six letters it contains, remove one letter and 12 remain. What is it?

John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?

Find the hidden tiger in the given optical illusion ?

Count The number of F's in the paragraph below:

"FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS"

What's the only room from which no one can enter or leave

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

Two guards were guarding the camp.Guard-1 was looking towards the south to make sure no threat is coming from the road.Guard-2 was looking at the north to make sure no threat is coming from the top. Suddenly Guard-1 ask the Guard-2 why he is smiling?How Guard-1 knows that Guard-2 is smiling?