ma puteti ajuta?????

Răspuns:
x/3 = y/4 = z/6 = k
x=3k
y=4k
z=6k
____+
13k=3900 =>k=300
x=900 ; 900+900•8/100=972
y=1200 ; 1200+1200•8/100=1296
z=1800 ; 1800+1800•8/100=1944