In a local cellular phone area,company A accounts for 60% of the cellular phone market,while company B accounts for the remaining 40% of the market.Of the cellular calls made with company A,1% of the calls will have some sort of interference,while 2% of the cellular calls with company B will have interference.If a cellular call is selected at random,the probability that it will have interference is
A)0.014
B)0.028
C)0.14
D)0.986

Question

Quizplus · Accepted Answer

The probability that a call will have interference is the sum of the probabilities that the call is made with company A and has interference, and the probability that the call is made with company B and has interference. The probability that a call is made with company A is 0.6, and the probability that a call made with company A has interference is 0.01. So the probability that a call made with company A has interference is 0.6 * 0.01 = 0.006. The probability that a call is made with company B is 0.4, and the probability that a call made with company B has interference is 0.02. So the probability that a call made with company B has interference is 0.4 * 0.02 = 0.008. The probability that a call has interference is 0.006 + 0.008 = 0.014.

In a Local Cellular Phone Area,company a Accounts for 60