You have two unmarked containers, a 9-liter container and a 4-liter container, and an unlimited supply of water. Explain how you would get an exact measurement of 3-liters with the given equipment.

1. Fill the four liter bottle with water first.

2. pour the four liter bottle into the nine liter making the four liter bottle empty and having 4/9 in the other

3. Refill the four liter bottle

4. Pout the four liter bottle into the nine making the four again empty and the nine have 8/9

5. refill the four liter one last time.

6. Finish filling the nine liter with water from the four liter. Making the nine liter full and the four 3/4th full leaving 3 liters in the bottle.