Relations and Functions

Question

# There are 200 individuals with skin disorder. 120 of them are exposed to chemical C1,50 to chemical C2 and 30 to both C1 and C2. Find the number of individuals :(i) exposed to chemical C1, but not to chemical C2.(ii) exposed to chemical C2 but not to chemical C1(iii) exposed to C, or chemical C2 or both.(iv) not exposed to any of the chemicals C1 and C2.

Set A = set of individuals exposed to chemical C
n(A) = 120                                                                                                           ....(i)
Set B = set individuals exposed to chemical C
n(B) = 50                                                                                                                      .... (ii)

Also,                        n (U) = 200                                                                                          ....(iii)

Using,     ,  we get

∴   (i) Number of individuals exposed to Cbut not to C2.

(ii) Number of individuals exposed to Cbut not to C1.

(iii) Number of individuals exposed to Cor C2.

(i) Number of individuals exposed to Cnor C2.

= 200 -140 = 60