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

What Word am I Looking For ?

A man says, "Brothers and sisters, have I none, but that man's father is my father's son." Who is that man?

What does this rebus means ?

Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

What is the fastest way to double your money?

Can you count the number of quadrilaterals in the picture below?

1 dollar = 100 cent
= 10 cent x 10 cent
= 1/10 dollar x 1/10 dollar
= 1/100 dollar
= 1 cent

=> 1 dollar = 1 cent

solve this tricky problem?

I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

You are in a room that has three switches and a closed door. The switches control three light bulbs on the other side of the door. Once you open the door, you may never touch the switches again. How can you definitively tell which switch is connected to each of the light bulbs?

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?