Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

Replace the question mark with the number below given a simple math problem.

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

What is full of holes but still holds water?

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

At a party, there are five people and a whole round cake lying at the centre of the table. Only four people will make a cut and take their piece and the last one will get the remaining piece on the table. How can they make sure that everyone gets a 1/5th of the piece?