Răspuns :
b + f + c = 85
b + f = 57
b + c = 46
c = 85 - 57
c = 28
b = 46 - c
b = 46 - 28
b = 18
f = 57 - b
f = 57 - 18
f = 39
b + f + c = 85
b + f = 57
b + c = 46
c = 85 - 57
c = 28
b = 46 - c
b = 46 - 28
b = 18
f = 57 - b
f = 57 - 18
f = 39
b + f + c = 85
b + f = 57
b + c = 46
c = 85 - 57
c = 28
b = 46 - c
b = 46 - 28
b = 18
f = 57 - b
f = 57 - 18
f = 39
b + f + c = 85
b + f = 57
b + c = 46
c = 85 - 57
c = 28
b = 46 - c
b = 46 - 28
b = 18
f = 57 - b
f = 57 - 18
f = 39