SOLUTION: A computer retail store has 8 personal computers in stock. A buyer wants to purchase 4 of them. Unknown to either the retail store or the buyer, 4 of the computers in stock have de

Algebra.Com
Question 1176464: A computer retail store has 8 personal computers in stock. A buyer wants to purchase 4 of them. Unknown to either the retail store or the buyer, 4 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 4 computers be chosen?
Answer: 8C4=70
b) What is the probability that exactly one of the computers will be defective?
Answer: (4)(4)=16 , 16/70
c)What is the probability that at least one of the computers selected is defective?

Answer by Boreal(15235)   (Show Source): You can put this solution on YOUR website!
a. is correct
b is (4C1)(4C3/8C4=16/70 correct
c. what is the probability NONE is defective, which is (4/8)(3/7)(2/6)(1/5)=24/1680=(1/70)
that is also (4C0)*(4C4)/8C4=1/70
at least one is defective is the complement of 1/70 or 69/70.

RELATED QUESTIONS

A computer retail store has 9 personal computers in stock. A buyer wants to purchase 4... (answered by VFBundy)
60% of large purchases made at a certain computer retailer are personal computer, 30% are (answered by Boreal)
A buyer wants to offer a pre- Easter special of leather handbags that will sell for $45... (answered by Theo)
A store has $50,000 of inventory in notebook computers and desktop computers. The profit... (answered by ikleyn)
Bailey is going to purchase 3 sports drinks from a convenience store. The store has a... (answered by reviewermath)
In 1998, there were 92,000 personal computer sold. By 2005, this figure has increased to... (answered by Fombitz)
A shipment of 8 similar computers to a retail outlet contains 3 that are defective. A... (answered by addingup)
Given that there are 12 computers on a shelf at the store and 3 are defective; what is... (answered by Boreal)
Two computers A and B are to be marketed. A salesman who is assigned the job of finding... (answered by ikleyn)