Respuesta :
Answer:
[tex]P(A) = 0.45[/tex]
[tex]P(B) = 0.32[/tex]
Step-by-step explanation:
Given
[tex]P(A) > P(B)[/tex]
[tex]P(A\ u\ B) = 0.626[/tex]
[tex]P(A\ n\ B) = 0.144[/tex]
Required
Find P(A) and P(B)
We have that:
[tex]P(A\ u\ B) = P(A) + P(B) - P(A\ n\ B)[/tex] --- (1)
and
[tex]P(A\ n\ B) = P(A) * P(B)[/tex] --- (2)
The equations become:
[tex]P(A\ u\ B) = P(A) + P(B) - P(A\ n\ B)[/tex] --- (1)
[tex]0.626 = P(A) + P(B) - 0.144[/tex]
Collect like terms
[tex]P(A) + P(B) = 0.626 + 0.144[/tex]
[tex]P(A) + P(B) = 0.770[/tex]
Make P(A) the subject
[tex]P(A) = 0.770 - P(B)[/tex]
[tex]P(A\ n\ B) = P(A) * P(B)[/tex] --- (2)
[tex]0.144 = P(A) * P(B)[/tex]
[tex]P(A) * P(B) = 0.144[/tex]
Substitute: [tex]P(A) = 0.770 - P(B)[/tex]
[tex][0.770 - P(B)] * P(B) = 0.144[/tex]
Open bracket
[tex]0.770P(B) - P(B)^2 = 0.144[/tex]
Represent P(B) with x
[tex]0.770x - x^2 = 0.144[/tex]
Rewrite as:
[tex]x^2 - 0.770x + 0.144 = 0[/tex]
Expand
[tex]x^2 - 0.45x - 0.32x + 0.144 = 0[/tex]
Factorize:
[tex]x[x - 0.45] - 0.32[x - 0.45]= 0[/tex]
Factor out x - 0.45
[tex][x - 0.32][x - 0.45]= 0[/tex]
Split
[tex]x - 0.32= 0 \ or\ x - 0.45= 0[/tex]
Solve for x
[tex]x = 0.32\ or\ x = 0.45[/tex]
Recall that:
[tex]P(B) = x[/tex]
So, we have:
[tex]P(B) = 0.32 \ or \ P(B) = 0.45[/tex]
Recall that:
[tex]P(A) = 0.770 - P(B)[/tex]
So, we have:
[tex]P(A) = 0.770 - 0.32 \ or\ P(A) =0.770 - 0.45[/tex]
[tex]P(A) = 0.45 \ or\ P(A) =0.32[/tex]
Since:
[tex]P(A) > P(B)[/tex]
Then:
[tex]P(A) = 0.45[/tex]
[tex]P(B) = 0.32[/tex]