Your answer is 2,200 pupils.
If 990 is equal to 45% of the total amount of pupils, then to find 1% we can divide both 45 and 990 by 45.
990 ÷ 45 = 22, which is 1%, so then we multiply 22 by 100 to get 100% of the pupils, which gives us 2,200.
I hope this helps!
