1. The problem statement, all variables and given/known data Prove: If a|b and b|c then a|c. Assume a, b and c are integers. 2. Relevant equations none 3. The attempt at a solution If a divides b then that means that there is a real integer "r" that is ra=b . and since we assume b divides c then c=bs. After here I got stuck. I was thinking maybe subsitute b and c for ar and bs, but it doesnt seem to get me anywhere. Thanks in advance.