If a salesperson has gross sales over 600000 in a year he or

If a salesperson has gross sales over $600,000 in a year, he or she is eligible to play the company\'s bonus game: A black box contains 1 twenty-dollar bill, 2 five-dollar bills, and I one-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 the maximum bonus, $31,000, by drawing out all bills in the box?

Solution

The box contains 1 twenety $ bill, 2 five $ bills and 1 one $ bill;
For maximum bonus of 31,000$ the 20 $ bill will have to be drawn in the end;

SO out of the total 4 notes (1 0f 20$, 2 of 5$ and 1 of 1$) the 20$ note has to come in the end;
Total 4 places are available in terms of order of drawing, probability of drawing a note in each place = 1/4
Thus probability of drawing the 20$ note in the end =1/4

Thus to gain maximum bonus of 31,000$ , his probability is =1/4