Solve all your doubts with Teachoo Black (new monthly pack available now!)

Examples

Example 1

Example 2 Important

Example 3

Example 4

Example 5 Important

Example 6 (i)

Example 6 (ii) Important

Example 6 (iii)

Example 6 (iv)

Example 6 (v)

Example 7 Important

Example 8 (i)

Example 8 (ii)

Example 9 Important

Example 10

Example 11 Important

Example 12

Example 13 Important

Example 14

Example 15

Example 16

Example 17

Example 18 Important

Example 19

Example 20

Example 21

Example 22 Important

Example 23

Example 24 Important

Example 25 Important

Example 26

Example 27 Important You are here

Example 28

Example 29 Important

Example 30

Example 31 Deleted for CBSE Board 2023 Exams

Example 32 Important

Example 33 Important

Example 34 Important

Chapter 1 Class 11 Sets

Serial order wise

Last updated at Jan. 27, 2020 by Teachoo

Example 27 There are 200 individuals with a skin disorder, 120 had been exposed to the chemical C1, 50 to chemical C2, and 30 to both the chemicals C1 and C2. Find the number of individuals exposed to (i) Chemical C1 but not chemical C2 Number of people exposed to chemical C1 but not Chemical C2 = Number of people exposed to chemical C1 – Number of people exposed to both chemical C1 & C2 People exposed to only chemical C1 People exposed to both chemical C1 & C2 = 120 –30 = 90 Hence, the number of individuals exposed to chemical C1 but not to chemical C2 is 90. Example 27 There are 200 individuals with a skin disorder, 120 had been exposed to the chemical C1, 50 to chemical C2, and 30 to both the chemicals C1 and C2. Find the number of individuals exposed to (ii) Chemical C2 but not chemical C1 Number of people exposed to chemical C2 but not Chemical C1 = Number of people exposed to chemical C2 – Number of people exposed to both chemical C1 & C2 People exposed to only chemical C2 People exposed to both chemical C1 & C2 = 50 – 30 = 20 Thus, the number of individuals exposed to chemical C2 and not to chemical C1 is 20 Example 27 There are 200 individuals with a skin disorder, 120 had been exposed to the chemical C1, 50 to chemical C2, and 30 to both the chemicals C1 and C2. Find the number of individuals exposed to (iii) Chemical C1 or chemical C2 Let U denote the universal set consisting of individuals suffering from the skin disorder, A and B denote the set of individuals exposed to the chemical C1 & chemical C2 respectively Number of people with skin disorder = n(U) = 200, Number of people exposed to chemical C1 = n(A) = 120 Number of people exposed to chemical C2 = n(B) = 50 Number of people exposed to both chemical C1 & C2 = n (A ∩ B) = 30 Number of individuals exposed either to chemical C1 or to chemical C2 = n(A ∪ B) We know that n (A ∪ B) = n (A) + n (B) – n (A ∩ B) = 120 + 50 – 30 = 140 Thus, 140 individuals are exposed either to chemical C1 or to chemical C2