The first thing we are going to do for this case is define variables.
We have then:
x = Number of boys
y = Number of girls
We now write the system of equations:
x / y = 11/9
x = y + 124
Solving the system we have:
x = 682
y = 558
The number of students is:
x + y = 682 + 558 = 1240
Answer:
the total students in the school is:
1240 students