Question

cate numere naturale a verifica inegalitatile: 1 supra 3 < a supra 45 < 4 supra 9

Answer 1

1/3<a/45<4/9
Aducem,la,numitor,comun,care,este,45,si,avem
15<a<20=>a,apartine{16,17,18,19}