Question

Un caiet si o carte costa 42 de lei .Aceiasi carte si un ghiozdan costa 244 lei , iar acelasi caiet si acelasi ghiozdan costa 208 lei .
Cat costa fiecare obiect ?

Answer 1

a- caiet
b-carte
c-ghiozdan

a+b=42
b+c=244=>b=244-c
a+c=208=>a=208-c

208-c+244-c=42
452-2c=42
452-42=2c
410=2c
c=205 costa un ghiozdan

b=244-205=39 o carte
a=208-205=3 un caiet

Answer 2

x+y=42
x+z=244
z+y=208
z=208-y
x=42-y
42-y+208-y=244
-2y=-6
2y=6
y=3
x=39
z=205