Answer:
0.416
Step-by-step explanation:
This problem is solve by using Baye's Probability.
Let P(U1) = Probability that Urn I is selected = 1÷3
P(U2) = Probability that Urn II is selected = 1÷3
P(U3) = Probability that Urn III is selected = 1÷3
Alos Let, R = Red ball is chosen
and W = White ball is chosen
Then, P(R/U1) = 3÷8
P(W/U1) = 5÷8
P(R/U2) = 4÷8
P(W/U2) = 4÷8
and, P(R/U3) = 5÷8
P(W/U3) = 3÷8
Then by Baye's Theorem,
[tex]P(U3| R) = \dfrac{P(R/U3) \times P(U3)}{P(R/U1) \times P(U1) + P(R/U2) \times P(U2) + P(R/U3) \times P(U3)}[/tex]
⇒ [tex]P(U3| R) = \dfrac{\frac{5}{8} \times\frac{1}{3} }{\frac{3}{8} \times\frac{1}{3}+\frac{4}{8} \times\frac{1}{3}+\frac{5}{8} \times\frac{1}{3}}[/tex]
⇒ P(U3| R) = 0.416
which is required probability.