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(1 point) A computer retail store has 11 personal computers in stock. A buyer wa

ID: 3353513 • Letter: #

Question

(1 point) A computer retail store has 11 personal computers in stock. A buyer wants to purchase 2 of them. Unknown to either the retail store or the buyer, 2 of the computers in stock have defective hard drives. Assume that the computers are selected at random (a) In how many different ways can the 2 computers be chosen? answer. (b) What is the probability that exactly one of the computers will be defective? answer. (c) What is the probability that at least one of the computers selected is defective? answer.

Explanation / Answer

Ans:

a) 11C2 = (11×10) / (2×1) = 55 ways

b)both defective 2/11*1/10 = 2/110
first defective second ok 2/11 *9/10 = 18/110
first ok second defective 9/11*2/10 = 18/110
first ok second ok 9/11* 8/10 = 72/110

P(X =1) = (18+18)/110= 36/110 =0.3273
3) P(x>=1) = 1 - no computers defective=1-72/110 = 38/110 = 0.3455