



 
Hi Jordan, Suppose the speed current is c miles per hour and it took Sammy t hours to go the 12 miles upstream. Going upstream his speed is (4  c) miles per hour and hence
Downstream his speed is (4 + c) and it takes him (8  t) hours to go the 12 miles so
Solve the first equation for t, substitute into the second equation an solve for c. Make sure you check your answer,  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 