h=human

b=big monkey

s=small monkey

1. Row b and s over ( hhhs / bs ) 2. Row b back ( hhhbs / s ) 3. Row b and s over ( hhh / bss ) 4. Row b back ( hhhb / ss ) 5. Row h and h over ( hb / hhss ) 6. Row h and s back ( hhbs / hs ) 7. Row h and b over ( hs / hhbs ) 8. Row h and s back ( hhss / hb ) 9. Row h and h over ( ss / hhhb ) 10. Row b back ( bss / hhh ) 11. Row b and s over ( s / hhhbs ) 12. Row b back ( bs / hhhs ) 13. Row b and s over ( / hhhbss )

Here is a remark on this problem I received from Rob Pratt, Department of Mathematics of The University of North Carolina at Chapel Hill,

I got this one from a Usenet archive on math problems which can be accessed here, look under logic problems, part 2.

Michael Shackleford, A.S.A.