Question

40 alunos representam 80% de um total de ?

Answer 1

regra de 3 

40 ------ 80% 
x --------100% 

multiplica cruzado 

80x = 40 . 100

80x = 4000

x = 4000/80 

x = 50 alunos             ok

Answer 2

40 ------ 80%

 x  ------ 100%

80x = 40 . 100
80x = 4000
x = 4000 / 80
x = 50 alunos