Solution:

8

Explanation:
If you look carefully then you will see that five matches lay ahead of the lighter and five are visible in the reflection of the lighter. Out of those five, we can see three matches emerging away from the surface of the lighter but two remains just as a part of reflection. Thus the total number of matches are eight.

Solution:

54325

Explanation:

Consider 1 = 5
2 = 25
3 = 325
4 = 4325
Then 5 = 54325

See the pattern. With every digit, the previous numbers are added after that digit

So the next number in the series is 54325

Solution:

Cycle

Solution:

Adam and Eve were the only people without navel. As they were not born out of a mother, they never had umbilical cords and thus never had navels.

Solution:

Align the toothpicks to form TEN. Use one toothpick for each of the lines.

Solution:

Four

As the window was closed it is obvious that the six candles that were not extinguished were lit till they melted away entirely. Thus only four candles that were extinguished remain at the end.

Solution:

What

Solution:

XIX is the answer which refers to nineteen in roman numeric system. On taking out one i.e. I, we will get XX that is equal to twenty.

Solution:

99 matches.

The number of matches will always sum up to one less than the number of players in a knock out tournament. You may calculate it in any manner. Thus 99 matches were played.

Solution:

I + IX = X

The equation read from the other side becomes X = XI + I which is false.