In a group of 65 people, 40 like cricket, 10 like both cricket and tennis. How many like tennis only and not cricket? How many like tennis?

Set  A = set of people who play cricket
Set B = set of people who play tennis
                                                                            ....(i)
                   
                   n(A)  = 40                                                                                   ....(ii)
                                                                              .....(iii)
Using,
                     65 = 40 + n(B)  -10
     n(B) = 65 - 40 + 10 = 35
Hence, (a) Number of people who play tennis = n(B) = 35
Number of people who play tennis only = n(B-A)