If a salesperson has gross sales of over $600,000 in a year, then he or she is eligible to play the company's bonus game: A black box contains 2 one-dollar bills, 1 five-dollar bill and 1 twenty-dollar bill. Bills are drawn out of the box one at a time without replacement until a twenty-dollar bill is drawn. Then the game stops. The salesperson's bonus is 1,000 times the value of the bills drawn. What is the probability of winning a $21,000 bonus?
