Let's see how well you can cope with this portion of intriguing math riddles.

Question 1:

In a rectangular room there are 10 chairs. It is possible to arrange the chairs in such a way so that an equal number of chairs is set against each wall of the room.

A cowboy was looking after 100 animals (oxen, cows and calves). For his job he was paid $100 (for every ox he received $10, for every cow $5 and for every calf $0.5). How many were the oxen, the cows and the calves?

A farmer had 9 cows. The first one produced 1 gallon of milk, the second one 2 gallons and so on. The ninth cow produced 9 gallons of milk. The farmer had three sons and he wanted to divide the cows in such a way that each of his sons received an equal number of cows and the cows of each produced an equal amount of milk. Is that possible?

In a lake there were lilies. The strange thing about them was that they doubled their number once per day. If on the 15th day half of the lake was covered with lilies, on which day will the whole lake be covered with them?

A peasant buys a pregnant sheep, which gave birth to a lamb. At the age of 3, the lamb gives birth to another lamb. After that it starts bearing a lamb per year. How many sheep will the peasant have 9 years after the birth of the first lamb if all the lambs are female and none of them ever dies?

A farmer had a yard, whose shape was a square, and in the four corners of this square there were apple trees. Some years later the farmer decided to make his yard twice as big and preserve the square shape. However, after the enlargement the four apple trees were still by the fence.