a/2=k a=2k
b/3=k b=3k
c/4=k c=4k
d/6=k d=6k
a+b+c+d=2k+3k+4k+6k=300
15k=300
k=300/15=20
a=2x20 =40
b=3x20=60
c=4x2=80
d=6x20=120
verificare 40+60+80+120=300
b) a : 1/2 =k a = k/2
b: 1/3 =k b=k/3
c: 1/4=k c=k/4
a+b+c= 130
k/2+k/3+k/4=130
6k+4k+3k=130*12
13k=1560
k= 120
a=120/2=60
b=120/3=40
c=120/4=30
verificare 60+40+30=130