An experiment has three possible outcomes: A, B, and C. If P(A)= P(B)and P(C)= 2P(A), what is the probability of each?

Can anyone help me get started?

User Icon for Marth Marth answered
14 years ago

Consider that P(A) + P(B) + P(C) = 1.

User Icon for Rmz Rmz answered
14 years ago

What do you mean?

User Icon for Marth Marth answered
14 years ago

The sum of the probabilities of each outcome must equal 1. Therefore, you can find the probability of any outcome by algebra.

P(A) + P(B) + P(C) = 1

I'll start you off.

Let x = P(A).

"P(A)= P(B)and P(C)= 2P(A)"

Then x = P(B) and 2x = P(C).

x + x + 2x = 1

User Icon for Rmz Rmz answered
14 years ago

So say I got x=1/4 would I substitute it in for P(A through C)?

User Icon for Marth Marth answered
14 years ago

Yes. x = 1/4, so P(A) = x = 1/4. Similarly, you can find P(B) and P(C).

User Icon for Rmz Rmz answered
14 years ago

Alright I think I got it

P(A)= 1/4
P(B)= 2/5
P(C)= 5/14

RIght?

User Icon for bobpursley bobpursley answered
14 years ago

Really good work.

User Icon for Marth Marth answered
14 years ago

"P(A)= P(B)and P(C)= 2P(A)"

We found that P(A) = x = 1/4. Therefore, P(B) = P(A) = x = 1/4.

P(C) = 2P(A) = 2x = 1/2

You can see that P(A) + P(B) + P(C) = 1/4 + 1/4 + 1/2 = 1

User Icon for Explain Bot Explain Bot answered
11 months ago

Of course! To find the probabilities of A, B, and C, we can start by assigning a variable to one of the probabilities and expressing the other probabilities in terms of that variable.

Let's say the probability of A is x. Since P(A) = P(B), the probability of B is also x.

According to the given information, P(C) = 2P(A). Substituting the value of P(A) with x, we can say P(C) = 2x.

Now, to find the overall probability, we sum up the probabilities of all possible outcomes, which should equal 1.

P(A) + P(B) + P(C) = 1

Substituting x for P(A) and x for P(B), we have:

x + x + 2x = 1

Simplifying the equation, we get:

4x = 1

To find x, we divide both sides by 4:

x = 1/4

So the probability of A (P(A)) and B (P(B)) is 1/4, and the probability of C (P(C)) is 2 times that:

P(A) = 1/4
P(B) = 1/4
P(C) = 2/4 = 1/2

Therefore, the probabilities are:
P(A) = 1/4
P(B) = 1/4
P(C) = 1/2