## tomo 2 years ago The population of registered voters contains 45% republicans and 55% democrats. If 25% of republicans and 75% of democrats favor an issue, and a person who is chosen at random favors the issue, what is the probability that she was a democrat?

1. tomo

This is what i have come up with so far. P(republican) = .45 P(democrat) = .55 P(republican and favors) = .25*.45 P(democrat and favors) = .75 *.55 P(favor) = P(republican AND favors) + P (democrat AND favors) therefore P(democrat given that favors) = P(democrat and favors)/ (Pfavors)

2. blurbendy

Hm, well this is what I came up with. Still thinking about it. 45*4 republicans and 55*4 democrats, let If 25% of republicans favor an issue means=45 and 75% of democrats favor an issue means = 165 total who favours = 210 P of her to be democrat= 165/210 .785

3. blurbendy

No wait

4. tomo

yeah, I got .786 too. I was confused if the question was asking about P(democrat given that she favors the bill) or something like P(democrat and favors), but we are given that in the problem statement.

5. blurbendy

I'm pretty sure it's ~.785

6. blurbendy

Would be nice to get a second opinion though

7. kropot72

I get P(democrat) = 0.7857

8. tomo

same here. i just rounded up