19.
a + b + c = 3962
a = 3c
c : b = 2 rest 176 => c = (c - 176)/2
Inlocuim
3c + (c - 176)/2 + c = 3962
Amplificam
6c + c - 176 + 2c = 7924
9c = 8100
c = 900
a = 3c = 3×900 = 2700
b = (900 - 176)/2 = 362
21.
a + b + c = 1143
a : c = 2 rest 105 => a = 2c + 105
b : c = 5, rest 78 => b = 5c + 78
Inlocuim
2c + 105 + 5c + 78 + c = 1143
8c = 960
c = 120
a = 2c + 105 = 2×120 + 105 = 240 + 105 = 345
b = 5c + 78 = 5×120 + 78 = 600 + 78 = 678
