Exhibit 5-5.The number of homes sold by a realtor during a month has the following probability distribution: Refer to Exhibit 5-5.What is the probability that the realtor will sell at least one house during a month?
A)0.20
B)0.40
C)0.60
D)0.80

Question

Exhibit 5-5.The number of homes sold by a realtor during a month has the following probability distribution:  Refer to Exhibit 5-5.What is the probability that the realtor will sell at least one house during a month?
A)0.20 
B)0.40 
C)0.60 
D)0.80

Quizplus · Accepted Answer

The probability of selling at least one house is equal to the sum of probabilities of selling one, two, three or four houses. That means: 
P(at least one) = P(1) + P(2) + P(3) + P(4) = 0.40 + 0.30 + 0.20 + 0.10 = 0.80. Therefore, the best choice is D, which corresponds to 0.80.