Question

Se stie ca a+2b+c=51 si 2a+b+2c=42.Aflati a+b+c

Answer 1

a+2b+c = 51
a+c=51-2b
2a+b+2c=42
2(a+c)+b=42
inlocuim a+c
2(51-2b)+b =42
102-4b+b=42
60=3b   deci b=20
a+c =51-2*20=11
a+b+c=11+20=31