How many times can you subtract the number two from the number fifty?

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 wooden log balances equally on the scales when weighed with three-quarters of a pound and three-quarters of a wooden log.

Can you calculate the weight of the entire wooden log?

The Puzzle: A girl, a boy, and a dog start walking down a road.

They start at the same time, from the same point, in the same direction.

The boy walks at 5 km/h, the girl at 6 km/h.

The dog runs from boy to girl and back again with a constant speed of 10 km/h. The dog does not slow down on the turn.
How far does the dog travel in 1 hour?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

Do You See It?

Known by all without exception, Forever here, for your protection, Sometimes strong, sometimes weak, Right after the night I come - hot and chic. And while millions of miles away, I always get to you, I find my way. No life around could do without me, Can you guess what I might be?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

John’s parents have three sons: Snap, Crackle, and what’s the name of the third son?

What has one letter and starts with an E?