There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

Who always enjoys poor health?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

How far can you walk into the woods?

Can you identify the famous TV character from the rebus below?

No matter how little or how much you use me, you change me every month. What am I?

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

The more you take me, the more you leave me behind.
Who Am I?

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?