1 votes 1 votes Let $n,r\ $and$\ s$ be positive integers, each greater than $2$.Prove that $n^r-1$ divides $n^s-1$ if and only if $r$ divides $s$. Quantitative Aptitude isi2018-pcb-a general-aptitude quantitative-aptitude descriptive + – akash.dinkar12 asked May 12, 2019 akash.dinkar12 449 views answer comment Share Follow See 1 comment See all 1 1 comment reply Sourajit25 commented Apr 14, 2020 reply Follow Share This might help: https://math.stackexchange.com/questions/128007/xa-1-divides-xb-1-if-and-only-if-a-divides-b 0 votes 0 votes Please log in or register to add a comment.