Respostas

2014-07-14T14:14:40-03:00
X= copo 
y=água dentro do copo

x+y=325 ----->x=325-y
x+y/2=180

x+y/2=180
325-y+y/2=180
-y/2=180-325 
-y/2= -145 .(-1)
y= 2.145
y=290

x=325-290
x=35

O copo pesa 35g