Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

If two's company, and three's a crowd, then whats four and five ?

I look at you, you look at me I raise my right, you raise your left. What am I?

I cannot talk, but I always reply when spoken to. What am I?

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

If a zookeeper had 100 pairs of animals in her zoo, and two pairs of babies are born for each one of the original animals, then (sadly) 23 animals don’t survive, how many animals do you have left in total?

A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?

In the given picture, you can find two letters missing. When two particular letters are placed in the missing spots, you get an eight-letter word while reading in the anti-clockwise direction. Can you find out the missing letters and the missing word eventually?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

If it took eight men ten hours to build a wall, how long would it take four men to build it?