Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

In a concert, Christina is performing a dance show with her group.
At 10:00, she and her crew were dancing in an absolutely straight line. At that time Christina was standing in 4th position from both the front and back end of the row.

What was the size of her crew?

Prove that the below maths equation is true.

8 + 8 = 91

what's the probability of getting a king or a queen from a pack of 52 cards?

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

The chance of Mr John winning the lottery is 10%. All participants lined up and Mr John is 4th in the row. The first three participants lose the lottery.

What is the chance of Mr John now?

I am never scared but became petrified and can’t live in a house but would die to make one. What am I?

The more it dries, the wetter it becomes. Can you tell what it is?

You and your two friends are working in a multinational company. How can you three find out the average salary of you all without disclosing your own salary to the other two?