Probability method

Question

40% chance of rain over 3 days is what method to solve?

Answer 1

P(r)=.4

P(~r)=.6

Probability of no rain for 3 days

= .6^3 = .36(.6) = .216= 21.6%

P(r=0)

Probability of rain at least one of the 3 days = 1-.216= .784 = 78.4%

P(r=1,2, or 3)

Probability of rain all 3 days = .4^3 = .16(.4) = .064 = 6.4%= P(r=3)

Probability of rain 2 and only of the 3 days = 3C2(.4)^2(.6)=3(.16)(.6)=.288=28.8%

=P(r=2)= P(1,2,or3)-P(1)-P(3)=78.4-43.2-6.4=78.4-49.6=28.8%

P(r=1)= 3(.4)(.6^2)=.4(1.08)= .432=43.2%