What question can you never answer yes to?

In Greek mythology, the Sphinx sat outside of Thebes and asked this riddle of all travellers who passed by. If the traveller failed to solve the riddle, then the Sphinx killed him/her. And if the traveller answered the riddle correctly, then the Sphinx would destroy herself. The riddle:

What goes on four legs in the morning, on two legs at noon, and on three legs in the evening?

Oedipus solved the riddle, and the Sphinx destroyed herself.

Can you find the thief by just looking at the picture below?

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

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"

No matter how little or how much you use me, you change me every month. What am I?

You have two rectangular wires.

Both of them have property that when you light the fire from one end , it will take 60 minutes to get completely burn.

However, they do not burn at consistent speed (i.e it might be possible 1st 20% burn in 50 minutes and 80% can burn in 10 minutes).

So how could you measure 45 minutes ?

What is the next number?

77, 49, 36, 18 ?

Replace The Question Mark Below With the Correct Number.

2 {38} 3
4 {1524} 5
6 {3548} 7
8 {????} 9

What demands an answer, but asks no questions