Question

Which expression represents the series 1+5+25+125+625?

Answer 1

Hello,

s=1+5+25+125+625 is the sum of the 5 terms of the geometric serie 1,5,25... 1 is the  first term and 5 the ratio.


$s=\frac{5^{5} -1}{5-1}=\frac{3124}{4}=781$