4 Quarts of Water from 5 quart and 3 quart pails

If you had an infinite supply of water and a 5 quart and 3 quart pails, how would you measure exactly 4 quarts? What is the least number of steps you need?

Answer:

1. Fill 5 quart pail & Transfer to 3 quart pail 
  (5p = 2, 3p = 3)

2. Throw water of 3 quart pail & Transfer 5 quart pail water to 3 quart pail 
  (5p = 0, 3p = 2)

3. Fill 5 quart pail & Transfer to 3 quart pail 
  (5p = 4, 3p = 3)

You will be left with 4 quarts in 5 quart pail