## LMarieee Group Title You toss 3 coins . What is the probability that you get exactly 2 heads, given that you got at least 1 head? A tree diagram will help you answer this question one year ago one year ago

1. hba Group Title

There is one possibility where you get no heads. There are three possibilities where you get 1 head. There are three possibilities where you get 2 heads. There is one possibility where you get 3 heads. But we don't count the possibility where you get no heads at all. So we only have seven possibilities that we're dealing with. So, the odds are 3/7.

2. rajathsbhat Group Title

I think its 1/2.

3. hba Group Title

The tree diagram shows 8 equally likely possible outcomes. We must exclude the TTT outcome because it is given that you get at least 1 head. Count all of the branch paths that show exactly 2 heads. There are 3 of them. There are 7 possible outcomes because we eliminated one of them. Therefore, the probability of getting exactly 2 heads in this problem is 3/7.

4. LMarieee Group Title

where do you get the 7 from

5. hba Group Title

total number of outcomes

6. rajathsbhat Group Title

since you have 1 head, the possibilities withe the other 2 are: HH, HT, TH, TT. Since you need exactly 2 heads, 2 of the above 4 possibilities are desirable. therefore $P=\frac{2}{4}=\frac{1}{2}$

7. LMarieee Group Title

and how do you get the total number of outcomes

8. hba Group Title

|dw:1344087828228:dw|

9. hba Group Title

But we don't count the possibility where you get no heads at all. So we only have seven possibilities that we're dealing with.

10. LMarieee Group Title

Oh okay, I understand now. Thank you.

11. hba Group Title

You are welcome