Let four sections in the exam are S1,S2,S3 and S4. Each sections have certain cut off marks that students have to score at least to pass that section. In order to pass the exam, students have to score more than each sectional cut off individually. Here, each section have two choices. Pass → Those who score more than cut off or fail → Those who score less than cut off Total number of choices = 2 × 2 × 2 × 2 = 16 Number of choice, in which student get passed by clearing each sectional cut off = 1 × 1 × 1 × 1 = 1 Hence, number of ways in which student get fail = 16 – 1 = 15