Average marks of four sections = 60%
Average marks of A, B, C and D sections are 45%, 50%, 72% and 80% respectively.
Average marks of A and B = 48%
By using Allegation approach
Students in Section A = 4, B = 6, C = 5 and D = x
Number of marks = in Section A = 45 × 4 = 180
Section B = 50 × 6 = 300
Section C = 72 × 5 = 360
Section D = 80 × x = 80x
Average of four sections is 60
=840+80x=900+60x20x=60x=3The ratio of number of students in Sections A and D = 4 : 3