Răspuns :
a+b+c=281
c=a:2 a=cx2
(b-a):(a+c)=3 rest 1
b-a=3a+3c+1
b=4a+3c+1
2c+4a+3c+1+c=281
2c+4x2c+4c=280
14c=280
c=280:14
c=20
a=20x2=40
b=40x4+3x20+1=160+61=221
c=a:2 a=cx2
(b-a):(a+c)=3 rest 1
b-a=3a+3c+1
b=4a+3c+1
2c+4a+3c+1+c=281
2c+4x2c+4c=280
14c=280
c=280:14
c=20
a=20x2=40
b=40x4+3x20+1=160+61=221