Find the missing number in the sequence.

3 5/3 7/5 11/7 ? 17/11

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

There is something which you can be arrested for attempting but not for successfully completing.

If 21x = 79x, what is the value of x?

Who is generally closer to the kids, mom or dad?

(it's a funny riddle)

He runs but never walks. Murmurs, but never talks. Has a bed, but never sleeps. And has a mouth, but never eats?

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?

Readers with high attention to detail can spot the cheater in the exam hall in 5 seconds. Are you one of them? Test your visual skills now!

In two decks of cards, what is the least amount of cards you must take to be *guaranteed* at least one four-of-a-kind?

The host of a game show, offers the guest a choice of three doors. Behind one is a expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?