Question

12.Aflati suma tuturor numerelor naturale care inpartite la 8 dau catul 15

Answer 1

Restul poate fi: 0; 1; 2; 3; 4; 5; 6; 7.
n:8=15 rest 0      n=15×8=120
n₁:8=15 rest 1    n₁=15×8+1=120+1=121
n₂:8=15 rest 2    n₂=15×8+2=120+2=122
...................................................................
n₇:8=15 rest 7     n₇=15×8+7=120+7=127 

Suma nr.naturale care impartite la 8 dau catul 15:
120+121+122+123+124+125+126+127=988