### You have a 5-gallon bucket, a 3-gallon bucket, and a hose to fill them up. You need to get 4 gallons. But you have no means of measuring how many gallons are in each bucket (except knowing the bucket capacity). How can you be certain that you have 4 gallons?

#### Show Answer

**Fill-up the 3-gallon bucket and empty it in the 5-gallon bucket. Now, you have 3-gallons in 5-gallon bucket. Again, fill up the 3- gallon water again and empty it in 5-gallon bucket until it is completely filled. Now, you have 1-gallon left in the 3-gallon bucket. Throw away all the water from 5-gallon bucket. And empty out the 3-gallon bucket in 5-gallon bucket. Now you have 1-gallon in 5-gallon bucket. Again, fill up the 3-gallon bucket and pour it into 5-gallon bucket. Finally, you have 4-gallons in 5-gallon bucket.**