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

O T T F F S S ?

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 ?

If,

6 / 7 = 2
3 / 9 = 7
8 / 2 = 6

Then

4 / 5 = ?

The following sentence is false. The preceding sentence is true.
Are these two sentences true or false?

Which fur should we be getting from the Lion?

Move three sticks of the spiral below to form a square.

Two boys wish to cross a river. The only way to get to the other side is by boat, but that boat can only take one boy at a time. The boat cannot return on its own, there are no ropes or similar tricks, yet both boys manage to cross using the boat.

How?

When it is alive we sing, when it is dead we clap our hands. What is it?

Count the number of triangles in the below picture?

Riddle me this, Riddle me that,
What am I? I am made of wood, but you can't see me down?