How many times can you subtract the number two from the number fifty?

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?

A swan sits at the center of a perfectly circular lake. At an edge of the lake stands a ravenous monster waiting to devour the swan. The monster can not enter the water, but it will run around the circumference of the lake to try to catch the swan as soon as it reaches the shore. The monster moves at 4 times the speed of the swan, and it will always move in the direction along the shore that brings it closer to the swan the quickest. Both the swan and the the monster can change directions in an instant.
The swan knows that if it can reach the lake's shore without the monster right on top of it, it can instantly escape into the surrounding forest.

How can the swan successfully escape?

Which Travels Faster? Solve below famous picture riddle:

It belongs to you, but other people use it more than you do. What is it?

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

What does man love more than life, and hate more than death or mortal strife; that which satisfied men want; the poor have, and the rich require; the miser spends, the spendthrift saves, and all men carry to their graves?

The person who makes it has no need for it; the person who buys it has no use for it. The person who uses it can neither see nor feel it. What is it?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

How can a man go eight days without sleep?