In School A, 60% are boys and the number of girls in School B is 25% less than the number of boys in School A and the number of girls in School C is 60 more than that of School B and the total number of students in school B is 1300. Find the number of boys in School B, if the average number of girls in School A, B and C is 540.
a) 760
b) 720
c) 480
d) 540
e) None of these
Sol:
The number of boys in School A = 60x
Number of girls in School A = 40x
Number of girls in School B = 60x * 75/100 = 45x
Number of girls in School C = 45x + 60
(40x + 45x + 45x + 60)/3 = 540
130x + 60 = 1620
130x = 1560
x = 12
Number of boys in School B = 1300 – 45 * 12 =
1300 – 540 = 760
