a + b + c = 121
a : c = 10 rest 5 ==> a = 10×c+ 5
b : c = 5 rest 4 ==> b = 5 × c + 4
inlocuim in prima relatie in functie de c
10×c + 5 + 5×c + 4 + c = 121
16 × c = 121 - 9
16 × c = 112
c = 112 : 16
c = 7 (al 3-lea numar)
a = 10 × 7 + 5 = 75 (primul numar)
b = 5 × 7 + 4 = 39 (al 2-lea numar)
Verificare:
75 + 39 + 7 = 121
