I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

He runs but never walks. Murmurs, but never talks. Has a bed, but never sleeps. And has a mouth, but never eats?

What am I?

A rubber ball keeps on bouncing back to 2/3 of the height from which it is dropped. Can you calculate the fraction of its original height that the ball will bounce after it is dropped and it has bounced four times without any hindrance ?

What has one eye, but can’t see?

You walk into a room where there are three primates held in their respective cages:
1) A lion who is eating the flesh of a goat.
2) An orangutan who is playing with blocks.
3) A donkey who is sitting idle.

Who is the most intelligent primate in the room?

How many words can a quill made with the feather of a pigeon write with a 100ml bottle of black ink?

I cannot talk, but I always reply when spoken to. What am I?