Subscribe to our Youtube Channel - https://www.youtube.com/channel/UCZBx269Tl5Os5NHlSbVX4Kg

Last updated at Feb. 15, 2020 by Teachoo

Transcript

Example 17 Given three identical boxes I, II and III, each containing two coins. In box I, both coins are gold coins, in box II, both are silver coins and in the box III, there is one gold and one silver coin. A person chooses a box at coin. If the coin is of gold, what is the probability that the other coin in the box is also of gold?Let B1 : Selecting Box 1 having two gold coins B2 : Selecting Box 2 having two silver coins B3 : Selecting Box 3 having one gold and one silver coin G : The second coin is of gold We need to find the Probability that the other coin in the box is also of gold, if the first coin is of gold i.e. P(B1"|"G) P(B1"|"G) = (๐(๐ต_1 ).๐(๐บ|๐ต_1))/(๐(๐ต_1 ).๐(๐บ|๐ต_1)+๐(๐ต_2 ).๐(๐บ|๐ต_2)+๐(๐ต_3 ).๐(๐บ|๐ต_3)) "P(B1)" = Probability of selecting Box 1 = ๐/๐ ๐ท(๐ฎ"|B1") = Probability that second coin is of gold in Box 1 = ๐ "P(B2)" = Probability of selecting Box 2 = ๐/๐ ๐ท(๐ฎ"|B2")= Probability that second coin is of gold in Box 2 = ๐ "P(B3)" = Probability of selecting Box 3 = ๐/๐ ๐ท(๐ฎ"|B3") = Probability that second coin is of gold in Box 3 = ๐/๐ Putting values in formula, ๐("B1|" ๐บ) = (1/3 ร 1)/( 1/3 ร 1 + 1/3 ร 0 + 1/3 ร 1/2 ) = (1/3 ร 1)/( 1/3 ร [1 + 0 + 1/2] ) = 1/( 1 + 1/2 ) = 1/( 3/2 ) = ๐/๐ Therefore, required probability is 2/3

Examples

Example 1

Example 2

Example 3

Example 4

Example 5 Important

Example 6

Example 7 Important

Example 8

Example 9 Important

Example 10

Example 11 Important

Example 12 Important

Example 13 Important

Example 14 Important

Example 15 Important

Example 16

Example 17 Important You are here

Example 18 Important

Example 19 Important

Example 20 Important

Example 21 Important

Example 22

Example 23

Example 24 Important

Example 25 Important

Example 26 Important

Example 27

Example 28 Important

Example 29 Important

Example 30 Important

Example 31 Important

Example 32 Important

Example 33 Important

Example 34 Important

Example 35 Important

Example 36 Important

Example 37 Important

Chapter 13 Class 12 Probability

Serial order wise

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.