60% x+40%( 100-x)= 100 * 49.6%
x = 48 100-x = 52。
A: There are 48 boys and 52 girls.
(2) If there are y boys in school B, there are (100-y) girls.
Excellent rate of school B = [57% y+37% (100-y)]/100 = (0.2y+37)/100 (1).
Excellent rate of a school = [60% x+40% (100-x)]/100 = (0.2x+40)/100 (2)
( 1)-(2)De:[0.2(y-x)-3]/ 100 & gt； 0
0.2(y-x) > 3
y-x & gt； 15
y & gtx+ 1
That is, when there are more boys in school B than in school A 15, the excellent rate in school B is higher than that in school A. ..
Take a random example within this range. For example, there are 68 boys and 32 girls in B school.