There are six people in a family namely M, N, O, P, Q and R.

R and O are brother and sister.

N is the brother of Q's husband.
P is the father of M and grandfather of R.

How many male members are in the family?

Prove that twice of ten is the same as twice of eleven.

Three ants are going up a hill, one behind the other. The last ant then says to the other ants, 'There is an ant behind me!'' How come?

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

I am sure no one can have two things for dinner. what are they?

What has many teeth, but cannot bite?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

Three cars are driving on a track that forms a perfect circle and is wide enough that multiple cars can pass anytime. The car that is leading in the race right now is driving at 55 MPH and the car that is trailing at the last is going at 45 MPH. The car that is in the middle is somewhere between these two speeds.
Right now, you can assume that there is a distance of x miles between the leading car and the middle car and x miles between the middle car and the last car and also, x is not equal to 0 or 1.
The cars maintain their speed till the leading car catches up with the last car and then every car stops. In this scenario, do you think of any point when the distance between any two pairs will again be x miles i.e. the pairs will be x distance apart at the same time ?

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?