Question

Aflati suma nr care la impartirea cu 7 dau catul 5 si restul nenul

Answer 1

x:7=5,r=1,2,3,4,5,6
r=1⇒x=7*5+1=36
r=2⇒x=7*5+2=37
r=3⇒x=7*5+3=38
r=4⇒x=7*5+4=39
r=5⇒x=7*5+5=40
r=6⇒x=7*5+6=41
x∈{36,37,38,39,40,41}
36+37+38+39+40+41=
1+2+3+...+35+36+37+39+40+41-1-2-3-....-35=
41*42/2-(35*36/2)=
861-630=231