00:01
So we know the probability of a is equal to 0 .5.
00:04
The probability of b is equal to 0 .2.
00:08
And we know a and b are independent.
00:12
Therefore, we know how to find their intersection.
00:15
We take the product of their two probabilities.
00:18
So we'll take 0 .5 times 0 .2 and get 0 .1.
00:22
So we could draw the bend diagram of this situation if we want like this.
00:27
Here's a.
00:28
We know they intersect and we know that that intersection is point one and the probability of a is equal to point five so this region out here would be point four this region right here point one plus point one will add up to point two so that's the probability of b and we can see that when we find the answer for letter a we want to find the probability of the union a union b and so we take the probability of a plus the probability of b and subtract away the overlap, which is going to end up being 0 .6.
01:11
Now notice we could have looked at our picture and just said that this is a or b.
01:18
And a or b, you can see 0 .4 plus 1 plus 0 .1 plus 0 .1 is going to add up to 0 .6...