Answer:
P(A U B)=P(A)+P(B)
Step-by-step explanation:
Reading the options that we have for the answer, one of them (the first one) is the definition of being independent. A and B are independent if and only if P(A ∩ B)=P(A)*P(B).
So the first one IS necessary true for independent events and with this equation, option two and three are necessary true for independent events:
For definition of P(A | B)
P(A | B)= P(A ∩ B) / P(B)
And we replace P(A ∩ B) using the first option that we know it´s true:
P(A | B)= P(A)*P(B) / P(B)= P(A)
So P(A | B)=P(A) it´s true for A and B independent.
The same process goes to show P(B | A)=P(B)
Because of this, the only one of the options that could not be true for independent events is P(A ∪ B)=P(A) + P(B), and this happens because P(A ∩ B)=P(A)*P(B) applies but it could be different from 0 considering P(A ∪ B)=P(A) + P(B) - P(A ∩ B). We conclude this property (P(A ∪ B)=P(A) + P(B)) is not necessary true for A and B independent.
Answer: only one gambeler will win
Step-by-step explanation:
This one is easy.
<span>–8.6 = –4.1 + x
</span>
So, what you have to do is add 4.1 on both sides.
You do this because you want to get X alone. when you do,
-8.6+4.1=-4.5
X=-4.5
The answer is B
He rents for d days, but two days are free, so he pays for only d - 2 days.
The rental fee is $45 per day, so for d - 2 days, he pays 45(d - 2). The total he pays is $315, so the equation is
<u>45</u>(<u>d</u> - <u>2</u>) = <u>315</u>
Now we solve the equation to find d, the number of days.
45(d - 2) = 315
45d - 90 = 315
45d = 405
d = 9
The number of days is 9.
