Question

Calculati suma :4/13 + 8/13 ...... 104/13

Answer 1

[tex]\frac{4}{13}+\frac{8}{13}+....+\frac{104}{13}=\frac{4+8+...+104}{13}=\frac{4(1+2+3+...+26)}{13}=\\ =\frac{4\cdot \frac{26\cdot 27}{2}}{13}=\frac{2\cdot 26\cdot 27}{13}=2\cdot 2\cdot 27=4\cdot 27=\boxed{108} [/tex]