There are 7 jars of pills, each contains 20, 000 identical pills. Each good pill weighs 10g, but bad pills can be 1 or 2 grams heavier or lighter than good pills (that is, possible weights of bad pills are 8, 9, 11 and 12 gram). If you are allowed to use a very accurate scale only once, how do you determine which jars contain good pills and which jars contain bad pills, as well as what are the weights of bad pills?
