Complete the table series riddle by finding the number that can replace "??".

There was an aeroplane crash, every single person died, but two people survived. How is this possible?

You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer, how can you boil the egg for only two minutes?

John decided to give his bike 3 coats of paint. Which coat would go on the first?

Count the Triangle in the figure given below:

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who 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.

John has played 50 ODI's and his average is 50. How many runs should he score in his 51st ODI, so that his average score jumps to 51?

In a box, there is a jumble of 7 red balls, 6 blue balls, 5 green balls, and 4 yellow balls. What is the minimum number of balls, will you have to pick up so that you have at least 4 balls of the same colour?