Answer:
The answer is 0.6
Step-by-step explanation:
I find it helpful to setup a Venn Diagram when dealing with these. This chart is pretty useful when dealing with set notation.
Then, you can set this up as a system of equations. So, based on your problem, we can setup the system like this:
x + y + z = 0.8
y + z = 0.5
y = 0.3
If you solve this, you will get:
x = 0.3
y = 0.3
z = 0.2.
To get P(A), you x and y to get x + y = 0.6
