Răspuns :
notam Iulia=a; Daniela=b; Raluca=c
a+b+c=310
b=a+70
c=4a
a+a+70+4a=310
6a+70=310
6a=240
a=240:6=40
b=a+70=40+70=110
c=4a=4×40=160
a+b+c=310
b=a+70
c=4a
a+a+70+4a=310
6a+70=310
6a=240
a=240:6=40
b=a+70=40+70=110
c=4a=4×40=160
a+b+c=310 b=a+70 a= c:4 c=4a a+ a+70 +4a=310 6a=310-70 =240 a=240:6 a=40 lei Iulia b=a+70=40+70=110 lei Daniela c=4*a= 4*40=160 lei Raluca 40+110+160=310 lei