Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

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?

Why Aeroplane windows are round?

Complete the series by replacing "?" with the correct number.

ST ND RD TH '?'

Aaron, Brad, Christopher, Danny and Elvis decided to play a game of tiddlywinks. In this game they decided that one win will get 1 point for winning, 0 for losing and 1/2 in case of a tie.

They finished the game in alphabetical order and it was found that the scores were different for each person.

Based on the following two statements, can you find out the result of the individual games?
Brad: No one could finish like me, without a loss.
Elvis: No one played worse than me, I finished without a single win.

Solve the puzzle by telling what does below picture means.

Make the seating arrangement of 10 children in such a way that there are 5 rows with 4 children in each row.

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

What does the following BrainBat signifies?

ABCDEFGHIJKLMNOPQRSTUVWYZ

QQQQQQQQQQQQQQQQQQQQQQQQQ.