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?

A girl has as many brothers as sisters, but each brother has only half as many brothers as sisters. How many brothers and sisters are there in the family?

Can you find the key in the picture below?

Solve the below puzzle by replacing the question mark with the correct number.

3 6 12

4 8 16

5 10 ?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

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

When it's bad luck to meet a black cat?

What does this rebus means ?

PROG WORKRESS

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

Before Mount Everest was discovered, what was the highest mountain in the world?