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

What Word am I Looking For ?

One absent-minded ancient philosopher forgot to wind up his only clock in the house. He had no radio, TV, telephone, internet, or any other means for telling time. So he travelled on foot to his friend's place a few miles down the straight desert road. He stayed at his friend's house for the night and when he came back home, he knew how to set his clock. How did he know?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

Find the next number in the following series:
6, 14, 26, 98, __?

What came first, the chicken or the egg?

Out of three Friends John, Jacob and Jonny one of them is a king, one is a bureaucrat, and one is a Spy.

The king always tells the truth, the bureaucrat always lies, and the Spy can either lie or tell the truth.

John says: Jonny is a bureaucrat
Jacob says: John is a king
Jonny says: I am a Spy

Tell me, Who is the king, who is the bureaucrat, and who is the Spy?

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 largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

What goes through cities and fields, but never moves?

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?