Suppose on a given day, there is a 27% chance Emily will forget her wallet when going to work. What is the probability she forgets her wallet at least once in the next ten days she goes to work?

Question

I'm just confused on what process to use for this problem.

Answer 1

Annamarie,

p=27%=0.27 is the probability that she forgets her wallet, q=1-p=0.73 is the probability that she does not forget it.

Using the multiplication principle, 0.73¹⁰ is the probability that she takes her wallet with her 10 days in a row.This is the complement event of the original event in the question,

E=she forgets the wallet at least once in 10 days

Ec=she does not forget her wallet for 10 days.

P(Ec)= 0.73¹⁰

P(E) = 1- 0.7310 = 0.957