THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING:
In a shipment of 18 trucks to a local truck dealer,there are four trucks that don't have air conditioning.Assume that you select four trucks at random.
-What is the probability that two or fewer of the four don't have air conditioning?
A)0.7727
B)0.9814
C)0.8169
D)0.9242

Question

Quizplus · Accepted Answer

The probability of selecting a truck without air conditioning is 4/18 = 2/9. The probability of selecting a truck with air conditioning is 14/18 = 7/9. The probability of selecting two or fewer trucks without air conditioning is:(7/9)^4 + 4(7/9)^3(2/9) + 6(7/9)^2(2/9)^2 + 4(7/9)(2/9)^3 + (2/9)^4 = 0.9814