Answer
$0.035$
Work Step by Step
$P(X\lt3)=P(X=0)+P(X=1)+P(X=2)={20\choose0}p^0(1-p)^{20}+{20\choose1}p^1(1-p)^{19}+{20\choose2}p^2(1-p)^{18}=0.00079+0.00684+0.027=0.035$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.