Question

anca si diana au impreuna 90lei,anca si radu au 79lei,iar diana si radu au 97 lei Cati lei are fiecare?

Answer 1

a+d=90
a+r=79
d+r=97
adunam cele 3 ecuatii si obtinem
a+d+a+r+d+r=266
2a+2d+2r=266
2(a+d+r)=266
a+d+r=133
79+d=133=>d=54
a+97=133
a=36
36+r=79
r=43