The Better Business Bureau settles 65 of complaints it recei

The Better Business Bureau settles 65% of complaints it receives involving new car dealers. Suppose a sample of 120 complaints involving new car dealers is selected. Find the probability that Better Business Bureau settles less than 91 of these complaints.  

I am getting 0.9916 what am i doing wrong

=NORM.DIST(90.5,78,5.224940191,TRUE)

Solution

I see.

Maybe it wants you to stricly use binomial distribution.

In that case, please use

=BINOMDIST(90, 120, 0.65, TRUE)

And this will yield

P(less than 91) = P(at most 90) = 0.99285947 [ANSWER]