Answer:
The probability that it will rain in all 3 cities on that day
P(V∪ C∪S) = 0.93 = 93%
Step-by-step explanation:
Let 'V' be the event of rain in Vancouver
Given that the probability of rain in Vancouver
P( V) = 20% = 0.20
P( V⁻) = 1- P( V) = 1 - 0.20 =0.80
Let 'C' be the event of rain in Calgary
Given that the probability of rain in Calgary
P( C) = 65% = 0.65
P( C⁻) = 1- P( C) = 1 - 0.65 =0.35
Let 'S' be the event of rain in Saskatoon
Given that the probability of rain in Saskatoon
P( S) = 75% = 0.75
P( S⁻) = 1- P( S) = 1 - 0.75 =0.25
First we will prove that the probability that it will not rain in all 3 cities on that day
P( V⁻ ∩ C⁻ ∩ S⁻ ) = P( V⁻) P( C⁻) P(S⁻)
= 0.80 × 0.35 × 0.25
= 0.07
The probability that it will rain in all 3 cities on that day
P(V∪ C∪S) = 1-(P( V⁻ ∩ C⁻ ∩ S⁻ )
= 1 - 0.07
= 0.93
