Respuesta :
Answer:
1. P(AuB) = 0.85
2. P(AuB') = 0.4
3. P(A'uB') = 0.8
Step-by-step explanation:
Given that;
There are four different color.
P(A) i.e the event that the design color is red will be; [tex]\frac{1}{4}[/tex]
= 0.25
P(B) i.e the event that the font size is not the smallest one, = [tex]\frac{4}{5}[/tex]
=0.8
1).
Using Addition Rule;
P(AuB)= P(A) + P(B) - P(AnB)
P(AnB) = P(A) × P(B)
= 0.25 × 0.8
= 0.2
∴
P(AuB)= 0.25 + 0.8 - 0.2
= 0.85
Thus, the probability that A union B [ P(AuB) ] is 0.85.
2).
Using Addition Rule;
P(AuB') = P(A) + P(B') + P(AnB')
Here, we are asked to look for the Probability of A union B compliment.
The probability value for complementary event (B) is,
[tex]P\left( {B'} \right) = 1 - P\left( B \right)[/tex]
As such; Since P(B) = 0.8
[tex]P\left( {B'} \right) = 1 - P\left( 0.8 \right)[/tex]
[tex]P\left( {B'} \right) = 0.2[/tex]
P(AnB') = P(A) × P(B')
P(AnB') = 0.25 × 0.2
P(AnB') = 0.05
∴
P(AuB') can now be calculated as;
= P(A) + P(B') - P(AnB')
= 0.25 + 0.2 - 0.05
= 0.4
Thus, the probability of A union B complement [ P(AuB') ] = 0.4.
3).
P(A'uB') = P(AnB)' (according to DeMorgan's Rule)
P(A'uB') = 1 - P(AnB)
From above P(AnB) = 0.2
∴
P(A'uB') = 1 - 0.2
P(A'uB') = 0.8
Thus, the probability of A complement union B complement [ P(A'uB') ] = 0.8