Respuesta :
Answer:
Step-by-step explanation:
Given that Events D and E are independent, with P(D)- 0.6 and P(D and E) - 0.18.
P(D and E) = P(D)*P(E) (since independent)
Or P(E) = 0.3
Using this we find
P(Dor E) = [tex]0.6+0.3-0.18 =0.72[/tex]
QNo2
Since lights are independent
P(Both) = P(A) *P(B) =0.22 where A I light on and B second light on
P(AB') = P(A) P(B') = 0.33
When we add we get P(A) = 0.55
P(B) = [tex]\frac{P(AB)}{P(A)} =0.6[/tex]
the probability that the second light will be red when he reaches it
= P(B) = 0.60
Probabilities are used to determine the chances of an event.
- The true statement is: [tex]\mathbf{P(D\ or\ E) = 0.72}[/tex]
- The probability that the second light will be red when he reaches it is 0.40
(a) Events D and E
The given parameters are:
[tex]\mathbf{P(D) = 0.6}[/tex]
[tex]\mathbf{P(D\ and\ E) = 0.18}[/tex]
Since the events are independent, then:
[tex]\mathbf{P(D\ and\ E) = P(D) \times P(E)}[/tex]
Substitute known values
[tex]\mathbf{0.18 = 0.6 \times P(E)}[/tex]
Divide both sides by 0.6
[tex]\mathbf{0.3 = P(E)}[/tex]
Rewrite as:
[tex]\mathbf{P(E) = 0.3 }[/tex]
Also:
[tex]\mathbf{P(D\ or\ E) = P(D) + P(E) - P(D\ and\ E)}[/tex]
Substitute known values
[tex]\mathbf{P(D\ or\ E) = 0.6 + 0.3 - 0.18}[/tex]
[tex]\mathbf{P(D\ or\ E) = 0.72}[/tex]
So, the true statement is: [tex]\mathbf{P(D\ or\ E) = 0.72}[/tex]
(b) Traffic lights
Let A and B represent the lights being red
The given parameters are:
[tex]\mathbf{P(Both\ Red) = 0.22}[/tex]
[tex]\mathbf{P(AB' ) = 0.33}[/tex]
Add both equations
[tex]\mathbf{P(Both\ Red) +P(AB' ) = 0.22 + 0.33}[/tex]
[tex]\mathbf{P(Both\ Red) +P(AB' ) = 0.55}[/tex]
Rewrite as:
[tex]\mathbf{P(AB) +P(AB' ) = 0.55}[/tex]
Express as
[tex]\mathbf{P(A) \times P(B) +P(A) \times P(B' ) = 0.55}[/tex]
Factor out P(A)
[tex]\mathbf{P(A) \times [P(B) + P(B' )] = 0.55}[/tex]
Opposite probabilities add up to 1
[tex]\mathbf{P(A) \times1 = 0.55}[/tex]
[tex]\mathbf{P(A) = 0.55}[/tex]
Recall that: [tex]\mathbf{P(Both\ Red) = 0.22}[/tex]
So, we have:
[tex]\mathbf{P(A) \times P(B) = 0.22}[/tex]
Substitute [tex]\mathbf{P(A) = 0.55}[/tex]
[tex]\mathbf{0.55 \times P(B) = 0.22}[/tex]
Divide both sides by 0.55
[tex]\mathbf{P(B) = 0.40}[/tex]
Hence, the probability that the second light will be red when he reaches it is 0.40
Read more about probabilities at:
https://brainly.com/question/11234923