A hat contains six slips of paper numbered 1 through 6. A slip is drawn at random, the number is noted, the slip is replaced in the hat, and the procedure is repeated. What is the probability that...

A hat contains six slips of paper numbered 1 through 6. A slip is drawn at random, the number is noted, the slip is replaced in the hat, and the procedure is repeated. What is the probability that after three draws the slip numbered 1 was drawn exactly twice, given that the sum of the numbers on the three draws is 8.