Question

5 kg de struguri + 6 kg de banane=61 lei
6 kg de struguri + 5 kg de banane=60 lei
1 kg struguri=?
1 kg banane=?

Answer 1

{5s+6b=61    inmultim -6
{6s+5b=60     inmultim 5

{-30s-36b=-361
{30s+25b=300
  /     -11b=-61    inmultim -1
b=61/11
b=1,(54) lei deci≈1,55 lei
din 5s+6b=61 avem
5s+6·61/11=61
5s=61-366/11
5s=(61·11-366)/11
5s=305/11
5·11s=305
s=305/55
s=5,54 lei deci≈5,55lei