in a class the ratio of boys to girls is 3:2, if there are 11 more boys than girls, how many children are in the class

first we represent unknowns using variables,,

let x = number of boys
let y = number of girls
according to first statement, ratio of boys to girls is 3:2 or 3/2 . thus we can write,
x/y = 3/2 or
x = (3/2)*y
according to second statement, there are 11 more boys than girls, thus,
x = y + 11
substituting the relationship we ot earlier - the x = (3/2)*y - to this :
(3/2)*y = y + 11
1.5y = y + 11
1.5y - y = 11
0.5y = 11
y = 22 girls
substituting this to x = (3/2)*y
x = 1.5*22
x = 33 boys

hope this helps~ :)