Question

Se da A+B=19, B+C=21 si A+C=20.
Calculati A+B+C si determinati numerele A,B si C .
Rezolvare:
Va rog mult sa ma ajutati...*_*

Answer 1

A+B+B+C+A+C = 19+21+20 = 60 ⇒
2A+2B+2C = 60⇒ 2(A+B+C)=60⇒ A+B+C=60:2=30

19+C=30⇒ C=30-19=11
B+11=21⇒ B=21-11=10
A+11=20⇒ A=20-11=9