Respostas

2014-03-23T22:46:12-03:00
Simples regra de 3


X -----------------------100 %
28 ----------------------7%
Multiplicando cruzado teremos

X . 7 = 2800

X= 2800 /7 
X= 400
6 3 6
2014-03-23T22:46:46-03:00
100 -----------X
7 ------------28
7x=2800
x=2800/7
x=400