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

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

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

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?

What is the word or phrase?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

Solve the mathematical equation in the picture below.

Cristina leaves home and then she makes exactly 3 left turns and returns home where she found 2 girls wearing the mask.

Who are these two masked girls?

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 captain of a ship was telling this interesting story: "We travelled the sea far and wide. At one time, two of my sailors were standing on opposite sides of the ship. One was looking west and the other one east. And at the same time, they could see each other clearly." How can that be possible?