a)3 : 100 X s + s = 412
3s : 100 + s = 412
103 s =41 200
s= 41 200 : 103
s= 400 lei
b) 80 : 100 X 70 = 56 ( ziare se vand)
c) a+ b = 72
a = b+ 4
2b + 4 = 72
2b= 68
b= 34
a= 38
d)[s- ( 2: 5 X s)] :2 = 15
s- ( 2: 5 X s) = 30
(5s + 2s) : 5 = 30
7s = 150
s= 21, 43
