Replace the question mark with the correct number.

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

There are 100 bulbs in a room. 100 strangers have been accumulated in the adjacent room. The first one goes and lights up every bulb. The second one goes and switches off all the even-numbered bulbs - second, fourth, sixth... and so on. The third one goes and reverses the current position of every third bulb (third, sixth, ninth? and so on.) i.e. if the bulb is lit, he switches it off and if the bulb is off, he switches it on. All the 100 strangers progress similarly.

After the last person has done what he wanted, which bulbs will be lit and which ones will be switched off?

I was speeding and ran through a stop sign, yet two traffic officers who were there do nothing about it.

why?

What does below rebus means ?

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

An equation has been laid down using a few matchsticks. However, as you can see, the equation is not correct. Can you correct the equation if you are allowed to add or remove 5 matchsticks?

How many runs at maximum can a batsman score in a normal one-day match? Consider the fact that the conditions are ideal and there are no No Balls, no Wide Balls and no Extras in that match.