a+b+c=122
a=75% din b= 75/100 * b= 3/4 * b= 3b/4
a= 3b/4
b= 30% din c= 30/100 * c= 3/10*c= 3c/10
a= 3 * 3c/10 /4= 9c/10/4= 9c/10 * 1/4= 9c/40
a=9c/40
9c/40 + 3c/10 +c =122 aducem la acelasi numitor
9c+12c+40c =4880
61c=4880
c= 80
a= 9*80/40= 9*2= 18
b=3*80/10= 3*8=24
