00:01
For this question we have a spinner which has sections that have proportions of 4 over 9 for a, 2 over 9 for b, and 1 over 3 for a c.
00:19
And for question a, we're asked in two consecutive spins, what is the probability of a c followed by a c? this is the probability of getting a c on the first spin times the probability of getting a c on the second spin.
00:45
And this gives us a probability of 1 over 9.
01:00
And then for b we are asked in a single spin, what is the probability of obtaining a b given that the spinner did not land on a? so we can say the probability of b given a prime, where a prime means not a.
01:20
According to a basic probability axioms, a conditional probability like this is equal to the probability of b and a prime, divided by a the probability of a prime.
01:40
Now the event b and a prime means b has occurred and not a has also occurred.
01:50
The only outcome that satisfies both b occurring and a not occurring is the occurrence of b.
01:57
So this is equal to the probability of b in the numerator.
02:05
And the probability of a prime is the probability of either b or c...