it has been determined that a certain cell will survive for a given period of time is 0.2. What is the probability that at most 280 of 1500 of these cells will survive for this period of time?

Question

the answer should be in decimal form

Answer 1

Using a combination calculator at https://stattrek.com/online-calculator/binomial.aspx , I get the following result: P(280 or less) = .10335

Looking at it like there are 1500 trials with 280 or less success rate & a probability of success = 0.2