In three schools, Alpha Public School, Bright Future School and Crescent Academy, the number of students is 400, 360 and 440 respectively. The ratio of boys to girls in these schools is 3 : 2, 5 : 4 and 7 : 4 respectively. Find the percentage of girls among all the students of the three schools together.

ATQ, In Alpha Public School: Total students = 400 Ratio of boys to girls = 3 : 2 Total ratio parts = 3 + 2 = 5 Number of girls = 400 × 2/5 = 160 In Bright Future School: Total students = 360 Ratio of boys to girls = 5 : 4 Total ratio parts = 5 + 4 = 9 Number of girls = 360 × 4/9 = 40 × 4 = 160 In Crescent Academy: Total students = 440 Ratio of boys to girls = 7 : 4 Total ratio parts = 7 + 4 = 11 Number of girls = 440 × 4/11 = 40 × 4 = 160 Total number of girls = 160 + 160 + 160 = 480 Total number of students = 400 + 360 + 440 = 1200 Required percentage of girls = (Total girls/Total students) × 100 Required percentage = 480/1200 × 100 Required percentage = 40%