100 : a = x rest 10 ==> ax = 100-10 = 90
150 : a = y rest 15 ==> ay = 150-15 = 135
250:a = z rest 25 ==> az = 250-25 = 225
90 = 2×5×3^2
135=3^3 × 5
225 = 3^2 × 5^2
--------------------------
3^2 × 5 = 9 × 5 = 45 (numarul cautat)
100 : 45 = 2 rest 10
150 : 45 = 3 rest 15
250 : 45 = 5 rest 25