a+b+c=720
3/8*720=90lei primeste primul muncitor
720-90=630lei-restul pt ceilalti doi muncitori
b+c=630
3/4b=3/5b
15b=12c
b=12c/15
12c/15+c=630
27c15=15*630/15
c=15*630/27=9450/27=350
c=350lei primeste al treilea muncitor
b=630-350=280lei primeste al doilea muncitor