can you help me solve this

Question

A poll is given, showing 80% are in favor of a new building project.

If 7 people are chosen at random, what is the probability that fewer than 5 of them favor the new building project? 

Probability =    (Please show your answer to 4 decimal places)

Answer 1

Use binomial formula:

P(x successes in n tries) = n! p^x (1-p)^(n-x)

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x! (n-x)!

where n here = 7, p = 0.8.

to find probability x < 5, compute probability x = 5, 6 and 7, sum those probabilities, then subtract that probability from 1.