Question 914965
p(survive) = .80, n = 12
a) P(x=10) = binompdf(12, .80, 10) = .2835
b) P(x ≤ 10) = binomcdf(12, .80, 10) = .7251
Re: TY
Awesome! to hear You are able to check Your work using 
Your calculator functions: binompdf(), binomcdf() and normalcdf()
....
normalcdf with a number of applications:
P( to left of z-score) = normalcdf(-100,z) 
P( to right of z-score) = normalcdf(z,100) 
P(between to z-scores) = normalcdf(smaller z, larger z)
.... 
invNorm(.95) for finding z-score knowing the % is also another useful tool.

Wish You the Best in your Studies.