Jankord Jewelers permits the return of their diamond wedding rings,provided the return occurs within two weeks.Typically,10 percent are returned.If eight rings are sold today,what is the probability that fewer than three will be returned?

Question

Quizplus · Accepted Answer

We can use the binomial distribution with n=8 and p=0.1 to find the probability of fewer than three returns.

P(X<3) = P(X=0) + P(X=1) + P(X=2)
P(X=k) = (8 choose k) * 0.1^k * 0.9^(8-k)

P(X=0) = (8 choose 0) * 0.1^0 * 0.9^8 = 0.4305
P(X=1) = (8 choose 1) * 0.1^1 * 0.9^7 = 0.3826
P(X=2) = (8 choose 2) * 0.1^2 * 0.9^6 = 0.1488

P(X<3) = 0.4305 + 0.3826 + 0.1488 = 0.9619

Therefore, the answer is B.

Jankord Jewelers Permits the Return of Their Diamond Wedding Rings,provided