ten identical PCs are in the inventory of a dealer,one has a hidden defect.if 3 are to be shipped,and the computers are selected in such a way that each has the same probability of being shipped,find

I.the number of ways in which 3 of the 10 PCs can be selected for shipment.
II.the total number of ways in which 3 of the 10PCs can be selected so that the one with the hidden defect will be included for shipment.
III.the probability that the computer with the hidden defect will be shipped.

1 answer

I. 3C10

II. 3C10 - 3C9

III. II / I