Question 129403
we suppose that a is the number of students that are in the school, then
we transfert this sentence "we add the same number plus 2/5 of the number initial" to a variable X.
X=a+a+2/5a=(1+1+2/5)a
X=12/5a  (1)

we use the sentence "After transfering 1/40 of the new number obtained to another schoo , in the school 2223 students still remain"

(1-1/40)X=2223
X=(2223*40)/39
X=2280

and when we use (1) 12/5a=2280 then a=(2280*5)/12=950
the number of students there were at the begining est 950