Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

A man was just doing his job when his suit was torn. Why did he die three minutes later?

You are in a room that has three switches and a closed door. The switches control three light bulbs on the other side of the door. Once you open the door, you may never touch the switches again. How can you definitively tell which switch is connected to each of the light bulbs?

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

John is the son of Jacob.
So,
Jacob is the_____of John's father?

There is a unique number which when multiplied by any number from 1 to 6, we will get the new number that contains the same digits only.

Can you find that number?

Which tank will fill first?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?