In an examination, a question paper consists of 12 questions, divided into two parts i.e., Part I and Part II containing 5 and 7 questions respectively. A student is required to attempt 8 questions in all, selecting at least 3 from each part. In how many ways can the student select his questions? 

Total number of questions:
                                   Part I = 5
                                   Part II = 7
Number of questions to be attempted = 8
Minimum 3 from each part
Options are:
              3 form part I, 5 from part II,
                            Number of selections = 
                                                        = 210.                                                       ...(i)
                                             Or
               4 from part I, 4 from part II,
                      Number of selections = 
                                                  = 175                                                              ...(ii)
                                            Or
                5 from part I and 3 from part II.
                       Number of selections =                          ...(iii)
Hence, the total number of selections = 210 + 175 + 35 = 420.