Question

An urn contains 5 red and 7 green balls. Another urn contains 6 red and 9 green balls. If a ball is drawn from any one of the two urns, find the probability that the ball drawn is green.

Answer 1

The answer is 71/120.....hope it helps : )

Answer 2

• Number of urns = 2

• Probability of choosing urn I = Probability of choosing urn II = $\frac{1}{2}$  

• Probability of choosing green ball from urn I = $(\frac{1}{2} )(\frac{7}{12} )$

• Probability of choosing green ball from urn II = $(\frac{1}{2})(\frac{9}{15} )$

• Hence, the probability that the ball drawn from any of the two urns is green = $(\frac{1}{2})(\frac{7}{12}) + (\frac{1}{2})(\frac{9}{15})$

                   = $\frac{71}{120}$