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1. nine horses are entered in a horse race. If you "box" three horses (three are chosen and they can finish in any of the first 3 positions in the race), determine the probability that you will hold the winning ticket.

-->i tried this one... (3C1*3C2*3C3)/9C3 but my answer is 3/28, which is wrong, it should be 1/14

2. A drawer contains four red socks and five blue socks. Three socks are drawn one at a time and then put back before the next selection. Determine the probability that

i. exactly red socks are selected

--> i did this... [(4C2*5C3) + (4C1*5C4) + (4C0* 5C5)]/9C3 = 27/28, but it is wrong since the answer in the book is 304/729

ii. at least two red socks are selected

--> i dont get this one..