n : 4 = x rest 1 => n = 4x + 1 |+3
n : 5 = y rest 2 => n = 5y + 2 | +3
=> n + 3 = 4 × (x + 1)
=> n + 3 = 5 × (y + 1)
n + 3 = 4 × 5
n + 3 = 20
n = 20 - 3
n = 17 (cel mai mic numar )
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M20 - 3 = 20 × 6 - 3 = 120 - 3 = 117 (cel mai mic numar de 3 cifre care respecta conditiile cerintei)
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