What occurs twice in a week, once in a year but never in a day?

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

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

It has five wheels, though often think four, You cannot use it without that one more, You can put things in it, you can strap things on top, You can't find it in the market, but you can still go shop. What is it?

13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

If eleven plus two equals one, what does nine plus five equal?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

Find the 8 in the below-given Image.

You have four chains. Each chain has three links in it. Although it is difficult to cut the links, you wish to make a single loop with all 12 links. What is the fewest number of cuts you must make to accomplish this task?

Name the three-letter word that can complete the below words?

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

Which country gets ill every time?