The J.O.Supplies Company buys calculators from a non-US supplier.The probability of a defective calculator is 10 percent.If 3 calculators are selected at random,what is the probability that one of the calculators will be defective?
A) .0702
B) .0010
C) .2430
D) .7290

Question

Quizplus · Accepted Answer

We can solve this problem by finding the probability of selecting one defective calculator and two good calculators, and then multiplying by the number of ways to arrange these selections. 
The probability of selecting one defective calculator and two good calculators is: 
(0.1)(0.9)(0.9) + (0.9)(0.1)(0.9) + (0.9)(0.9)(0.1) = 0.243 
There are three ways to arrange these selections (defective calculator in position 1, 2, or 3), so we multiply by 3: 
0.243 * 3 = 0.729 
Therefore, the probability that one of the calculators will be defective is 0.729 or approximately 0.73. None of the other answer choices match this value, so the best choice is C.

The JOSupplies Company Buys Calculators from a Non-US Supplier