Answer:
40% are boys
900 are girls.
To get the total number of boys, that will be number of boys, divided by hundred multiply by total number of girls
i.e 40รท100 * 900= 360, we have 360 boys, to know the number of student add 900 to the number of boys which gives you 1,260.
the total number of students in the school is 1,260