Question 750493
X ~ Binomial(100, 0.8)
a. P(X ≥ 70) = {{{sum((matrix(2,1,100,x))(0.8^x)(0.2^(100 - x)),x = 70,100)}}} = {{{highlight(0.9939)}}}

b. P(X < 85) = {{{sum((matrix(2,1,100,x))(0.8^x)(0.2^(100 - x)),x = 0,84)}}} = {{{highlight(0.8715)}}}