Question

One in 100 tennis balls produced at a factory is defective. if you randomly select five tennis balls, what is the probability that at least one will be defective

Answer 1

You can tell this is a binomial distribution since there is specific failure or success (getting a defective is success, for example). 

X~B(5, 0.01)  

P(X≥1)= 1-P(X≤1) 
=1-(0.999)
=9.80×10⁴ probability of getting at least one that is defective. 

Hope I helped :)