Question

Buna am nevoie de ex 25
$va \: rog$
dau coroana

Answer 1

S=1+2+3+4+5+6+7+8+9+10+11+12 dă 78 e clar că 78-75=3 deci 1+2=3 cade și începi de la 3+4+5+6+7+8+9+10+11+12=75

Answer 2

[tex]\it I) \ n+n+1=75\Rightarrow 2n=74 \Rightarrow n = 37 \\ \\37+38=75 \\ \\ II) \ n+n+1+n+2=75\Rightarrow 3n=72 \Rightarrow n = 24 \\ \\ 24+25+26=75[/tex]

[tex]\it III) \ n+n+1+n+2+n+3=75\Rightarrow 4n=69\ (nu\ convine) \\ \\ \\ IV)\ n+n+1+n+2+n+3+n+4=75\Rightarrow 5n=65 \Rightarrow n = 13 \\ \\ 13+14+15+16+17=75 \\ \\ V) n+n+1+n+2+n+3+n+4+n+5=75\Rightarrow 6n=60 \Rightarrow n = 10 \\ \\ 10+11+12+13+14+15=75[/tex]

Analog, obținem:

[tex]\it VI)\ 7n=54 \ (nu\ convine) \\ \\ VII)\ 8n=47 \ (nu\ convine) \\ \\ VIII)\ 9n=39 \ (nu\ convine) \\ \\ IX)\ 10n=30 \Rightarrow n=3 \Rightarrow 3+4+5+6+7+8+9+10+11+12=75[/tex]