Question

A factory produces nails and packs them in boxes of 200. If the probability that a nail is substandard is 0.006. Find the probability that a box selected at random contains at most two nails which are substandard.

Answer 1

could be..
0 substandard ----> C(200,0) (.006)^0 (.994)^200 = ....
1 substandard ----> C(200,1) (.006)(.994)^199 = ....
2 substandard ---> C(200,2) (.006)^2 (.994)^198 = ....
add them up

Answer 2

0.6205

Answer 3

p(x=0) = 0.3001
p(x=1)=0.3623
p(x=2)=0.2176
p(x<3)=0.8800