Question

Ajutoor!!
1 pe 25+ 2pe 25+ 3 pe 25.....+ 24 pe 25

Answer 1

 $...=\frac{1+2+3+...+24}{25}=\frac{24\cdot25}{2}\cdot\frac{1}{25}=12$

Answer 2

1/25+2/25+3/25+...+24/25=(1+2+3+4+...+24)/25=
Se aplica formula de calcul a sumei primelor 24 numere naturale (nenule) consecutive (Formula lui Gauss) 1+2+3+4+...+24=24·(24+1):2=24·25:2=600:2=300  Reluam exercitiul 
=300:25=12