Question

Determinati toate nr naturale si nenule care :impartite la 5 dau catul de 2 ori mai mare ca restul.

Answer 1

n:5=c, r c=2r => n:5=2r, r r < 5 I. r=0 => n:5=2×0, r (0) => n=0×5+0 => n=0 -> fals, deoarece n diferit de 0 II. r=1 => n:5=2×1, r (1) => n=5×2+1 => n=10+1 => n=11 III. r=2 => n:5=2×2, r (2) => n=5×2×2+2 => n=22 IV. r=3 => n:5=2×3, r (3) => n=5×2×3+3 => n=33 V. r=4 => n:5=2x4, r (4) => n=5×2×4+4 => n=44