Why do we preferably have round manhole covers and not square ones?

Why do you find that most of the buildings are deprived of the 13th floor?

2 ladies and 2 girls need to cross a river in a boat big enough for 1 LADY or 2 girls. How do they do it?

An octopus has 8 legs. A hippogriff has 6 legs and 2 pairs of wings. A sphinx has 6 legs and one pair of wings. Now we have all 3 kinds and a total of 18 insects in a cage. We have a total of 118 legs and 20 pairs of wings. How many insects do we have of each kind?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

A farmer went to a market and bought a wolf, a goat, and a cabbage. On his way home, the farmer came to the bank of a river and rented a boat. But crossing the river by boat, the farmer could carry only himself and a single one of his purchases: the wolf, the goat, or the cabbage. If left unattended together, the wolf would eat the goat, or the goat would eat the cabbage. The farmer’s challenge was to carry himself and his purchases to the far bank of the river, leaving each purchase intact. How did he do it?

Can you count the number of squares in the given picture?

A cat had three kittens: Snophy, Topsy and Jorden. What was the mother's name?

This was asked in an interview with Coa-Cola.

The interviewer has given me 100 marbles(50 white and 50 black) and two empty boxes.
He then told me that he will leave the room and i need to place all the marbles in two boxes.

And When he come back, he will draw a marble from any of the two box and if the marble is white I will be hired.

Also
* No box can be empty.
* All 100 marbles must be placed in one of the two boxes.

So what should I have done?

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?