Acceptance Probability

Probability is chance.
We can break down question 1a by looking at how many good tv's we have in the pile every time we need to choose a tv. So
if 4 tv's of 6 work, we have a 4/6 (spoken 4 in 6) chance of choosing a good tv on the first round.
Once we pick one of the good tv's, the number of good tv's go down by 1 but so does the total number of tvs. Now we have 3/5 (spoken 3 in 5) chance of choosing another good tv the second round.

The answer would look like
4 x 3 (there would be a line between 4 and 6 and a line between 3 and 5)
6 5

multiply across and you get 12/30 or a 12 in 30 chance of choosing 2 good tv's from this pile

b) When "at least" is used, that means there are different ways to get the right combination. In this instance 2 tv's are being choosen and the following sequences satisfy the requirement:
a) broken tv then a good tv
b) broken tv then a broken tv
c) a good tv then a broken tv

We have to find the probability for each of these occurances and add them together
a) we have 2 in 6 chance of getting a broken tv on the 1st pick and 4 of 5 chance of getting a good tv on the second pick:
2 x 4 (lines between 2 and 6 and 4 and 5) multiply across and get 8/30
6 5

b) we have 2 in 6 chance of getting a broken tv on the 1st pick and 1 of 5 chance of getting a broken tv on the second pick:
2 x 1 (lines between 2 and 6 and 1 and 5) multiply across and get 2/30
6 5

c) we have 4 in 6 chance of getting a good tv on the 1st pick and 2 of 5 chance of getting a broken tv on the second pick:
4 x 2 (lines between 4 and 6 and 2 and 5) multiply across and get 8/30
6 5

now we add all of these occurances together:
8 plus 2 plus 8 (lines between the top and bottom numbers)
30 30 30
the answer is 18/30 or 18 in 30 chance of picking at least 1 broken tv when 2 are picked from this pile