Tree Diagrams 7 P Take a Test cynthia Davis Google Chrome h

Tree Diagrams - 7

P Take a Test cynthia Davis Google Chrome https:// 110724450&centerwin; yes Cynthia Davis 12/8/15 11:23 AM Quiz: 6.5 (quiz) Tree Diagrams Overview 1 2 3 4 6 7 8 6.5 (quiz) Tree Diagrams This Question: 1 pt This Test: 10 pts 0 of 10 Urn I contains 9 red balls and 9 white balls. Urn II contains 11 white balls. A ball is selected at random from urn I and placed in urn II. Then a ball is selected at random from urn II. What is the probability that the second ball is white The probability that the second ball is white is L Vi Vi Enter your answer in the answer box. Previous Question Next Question I Submit Quiz

Solution

URN I
n(red) = 9
n(white) = 9

URN II
n(white) = 11

A ball is selecetd at random from urn I, it may be either red or white & dropped into URN II. If chosen ball is red from URN I, URN II contains 12 white balls otherwise 11 white balls. The Probability that the second ball is white will be the combine of both case.

Case when chosen ball is red from URN I = 9 C 1 / 18 C 1 * 11 C 1 / 12 C 1

Case when chosen ball white from URN I = 9 C 1 / 18 C 1 * 12 C 1 / 12 C 1

Final Probability = 9 C 1 / 18 C 1 * 11 C 1 / 12 C 1 + 9 C 1 / 18 C 1 * 12 C 1 / 12 C 1
= (9*11 + 9*12) /18*12
= 0.9583