# Example 8 - Chapter 13 Class 12 Probability (Term 2)

Last updated at Feb. 15, 2020 by Teachoo

Last updated at Feb. 15, 2020 by Teachoo

Transcript

Example 8 An urn contains 10 black and 5 white balls. Two balls are drawn from the urn one after the other without replacement. What is the probability that both drawn balls are black? We need to find probability that both balls drawn out are black Now, Probability both balls drawn are black = Probability first ball drawn is black × Probability second ball is black if first is black Finding both probabilities separately Probability first ball drawn is black There are 10 blacks balls out of 15 So, Probability = 10/15 = 2/3 Probability second ball drawn is black if first ball was black If first ball drawn was black, we are left with 9 black, 5 white balls So, Probability = (𝑅𝑒𝑚𝑎𝑖𝑛𝑖𝑛𝑔 𝐵𝑙𝑎𝑐𝑘 𝑏𝑎𝑙𝑙)/(𝑅𝑒𝑚𝑎𝑖𝑛𝑖𝑛𝑔 𝑏𝑎𝑙𝑙𝑠) = 9/14 Therefore, Probability both balls drawn are black = Probability first ball drawn is black × Probability second ball is black if first is black = 2/3 × 9/14 = 𝟑/𝟕

Examples

Example 1

Example 2

Example 3

Example 4

Example 5 Important

Example 6

Example 7 Important

Example 8 You are here

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

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 Deleted for CBSE Board 2022 Exams

Example 28 Important Deleted for CBSE Board 2022 Exams

Example 29 Important Deleted for CBSE Board 2022 Exams

Example 30 Important Deleted for CBSE Board 2022 Exams

Example 31 Important Deleted for CBSE Board 2022 Exams

Example 32 Important Deleted for CBSE Board 2022 Exams

Example 33 Important

Example 34 Deleted for CBSE Board 2022 Exams

Example 35 Deleted for CBSE Board 2022 Exams

Example 36 Important

Example 37 Important

Chapter 13 Class 12 Probability (Term 2)

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 10 years. He provides courses for Maths and Science at Teachoo.