There are 8 cars in a parking lot on a very cold day. Suppose the probability of any of them not starting is 0.13. What is the probability that exactly 2 of the cars will not start?

1 Answer
May 15, 2018

I don't have a CAS on me right now but you can use the explanation to find the fraction form
Answer: 0.20519191831

Explanation:

Use binomial distribution formula:

#8C2(0.13)^2(1-0.13)^(8-2)#

Basically it's:
how many combinations are there for out of 8 cars, 2 won't start
#xx#
probability that two cars won't start #(0.13)^2#
#xx#
probability that the rest will start #(1-0.13)^(8-2)#

To solve it use the combination formula:

#(8!)/((8-2)!2!)xx(0.13)^2(1-0.13)^(8-2)#

#=28xx0.0169xx0.433626201=0.20519191831#