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

Question

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.

Answer 1

I. 3C10

II. 3C10 - 3C9

III. II / I