On average 72 students per section from the four sections ‘P’, ‘Q’, ‘R’ and ‘S’ passed an examination. The ratio of total number of students in the sections ‘P’, ‘Q’ and ‘R’ is 2:3:5, respectively and the average of number of students in sections ‘R’ and ‘S’ is 100. If 72% of the total number of students in given four sections passed the examination, then find the total number of students in section ‘Q’.

Given, the average number of students who passed the examination per section is 72. Total number of students who passed the examination from all the sections together = 72 × 4 = 288 Let the number of students in sections ‘P’, ‘Q’ and ‘R’ are ‘2x’, ‘3x’ and ‘5x’, respectively. Number of students in section ‘S’ = 2 × 100 – 5x = (200 – 5x) According to the question; (72/100) × {2x + 3x + 5x + 200 – 5x} = 288 Or, (18/25) × {5x + 200} = 288 Or, 5x + 200 = 400 Or, 5x = 200 So, x = 40 Number of students in section ‘Q’ = 3 × 40 = 120