Answer Number 4: 99 Days

Answer Number 5: An Egg

The Sixth Difficult Riddle

It is a fine day and you are standing at the river bank with a 5-gallon container and a 3-gallon container. Both are irregularly shaped. Strangely, you resolve to enjoy the day by filling the 5-gallon container with exactly 4 gallons of water? How do you accomplish it?

Seventh Difficult Riddle

A gardener is asked to plant five rows of cherry trees with four trees in each row. His employer gives him exactly enough money to buy twenty trees from the local nursery, and jokingly tells him that he can keep whatever change there is. On the way to the nursery, the gardener realizes that it if he buys just ten trees, it will still be possible to plant five rows with four trees in each, and he can keep half the money he has been given. How does he plan to plant the trees?