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

Which statement is true out of the following?
One statement here is false.
Two statements here are false.
Three statements here are false.

Before Mount Everest was discovered, what was the highest mountain in the world?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

Remove two matchsticks to make the below equation correct.

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

You are stuck on an island where you have nothing. You find four pieces of paper somewhere on the island. What will be your strategy to escape from the island safely?

PS: No other resource is available to you on the island, neither can you build anything.

A bomb exploded in a room full of married couples and no one died. How?

What do you get if you add 2 to 100 four times?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10