Agnes, Becky, Cindy and Delia crossed a lake in a canoe that held only two persons.
- The canoe held two persons on each of three forward trips across the lake and one person on each of two return trips.
- Agnes was unable to paddle when someone else was in the canoe with her.
- Becky was unable to paddle when anyone else but Cindy was in the canoe with her.
- Each person paddled continuously for at least one trip.
Who paddled twice?
For brevity, represent the girls by their first initial:
1) B&C go over, B paddles (allowed since C is with her)
2) C goes back alone (C has no restrictions)
3) A&D go over, D Paddles (D has no restrictions)
4) A goes back alone (allowed - A is alone)
5) A&C go over, and C must paddle due to the restriction on A
Therefore C, or Cindy paddles twice.
Posted by Kenny M
on 2013-01-17 20:46:21