In three different schools, Lotus High School, Silver Oak School and Pioneer Public School, the number of students is 400, 300 and 500 respectively. The ratio of boys to girls in these schools is 3 : 1, 1 : 2 and 7 : 3 respectively. Find the percentage of girls among the total students in all three schools.

ATQ, In Lotus High School: Total students = 400 Ratio of boys to girls = 3 : 1 Total ratio parts = 3 + 1 = 4 Number of girls = 400 × 1/4 = 100 In Silver Oak School: Total students = 300 Ratio of boys to girls = 1 : 2 Total ratio parts = 1 + 2 = 3 Number of girls = 300 × 2/3 = 200 In Pioneer Public School: Total students = 500 Ratio of boys to girls = 7 : 3 Total ratio parts = 7 + 3 = 10 Number of girls = 500 × 3/10 = 150 Total number of girls = 100 + 200 + 150 = 450 Total number of students = 400 + 300 + 500 = 1200 Required percentage of girls = 450/1200 × 100 Required percentage = 45/120 × 100 = 3/8 × 100 = 37.5%