A man dies of old age on his 25 birthday. How is this possible?

A maths symbol is hidden in the below Bar Graph. Can you decipher it?

I’m tall when I’m young, and I’m short when I’m old. What am I?

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.

Below toothpicks/matchsticks indicate the group of fishes moving from west to east direction. Can you make them move from east to west by just moving three toothpicks/matchsticks?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

I have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?

What 8 letter word can have a letter taken away and it still makes a word. Take another letter away and it still makes a word. Keep on doing that until you have one letter left. What is the word?

Can you name some countries which do not have the alphabet 'A' in them?

Find the number of squares in the below-given picture.