Answer:
2/3
Step-by-step explanation:
Well, it supplied the formula, so let's start from there.
P(A or B) = P(A) + P(B) - P(A and B)
Let A = the probability that the red die shows a number larger than three
Let B = the probability that the green die shows a number less than three
I'm assuming they both have 6 numbers on them, like a regular die.
So there are 3 possibilities that are larger than 3 (4, 5, and 6) and 6 total possibilities, so A = 3/6.
There are 2 possibilities that are less than 3 (1 and 2) and 6 total possibilities, so B = 2/6.
Plug that into the formula.
P(A or B) = 3/6 + 2/6 - P(A and B)
Now we have to subtract the probability that both A and B happen, which is 3/6 * 2/6 = 6/36 = 1/6.
P(A or B) = 3/6 + 2/6 - 1/6
P(A or B) = 4/6 = 2/3
