1. ## probability

An urn contains 5 red, and 2 green balls. A ball is chosen randomly and returned to the urn along with 6 more balls of the same color. Then, a ball is drawn again. Calculate the probability that the second ball is red (fraction in lowest terms).

2. ## Continuation of problem

Continuation: In the situation above, find the probability that both balls drawn are the same color (need not simplify).

3. Originally Posted by mhitch03
An urn contains 5 red, and 2 green balls. A ball is chosen randomly and returned to the urn along with 6 more balls of the same color. Then, a ball is drawn again. Calculate the probability that the second ball is red (fraction in lowest terms). In the situation above, find the probability that both balls drawn are the same color (need not simplify).
$P(R_2)=P(R_1R_2)+P(G_1R_2)=\frac{5}{7}~\frac{11}{1 3}+\frac{2}{7}~\frac{5}{13}$

$P(R_1R_2)+P(G_1G_2)=?$