The Cannibal/Missionary Puzzle

Miscellaneous and Personal Stuff I Must Share
1

I need help with a puzzle. It takes some imagination, so sit down…

Take 3 quarters and place one heads up, the other 2 tails up. Do the same with 3 pennies.

Now, the quarters represent missionaries, and the pennies represent cannibals. The “heads” quarter is the Head Missionary, and the “heads” penny is the Head Cannibal. Got that?

Now, imagine that the six characters are cavorting through the jungle and have to cross a river (an imaginary line on a table in front of you). The only way to get across the river is in a canoe (your hand). IOW, if you push a coin across the table, that represents one character making a trip across the river. With me so far?

Now, the idea is to get all 6 characters safely across the river. Here are the rules:

  1. Only the Head Cannibal OR the Head Missionary can pilot the canoe. IOW, each trip across the river must include at least one “Head.”

  2. At no time can there be more cannibals in one place than missionaries, lest the cannibals eat the missionaries. Example: if you send the Head Missionary across the river solo, that leaves 3 cannibals and 2 missionaries on 1 side; CHOMP!

  3. It is, however, perfectly acceptable to have more missionaries in any place than cannibals, as the missionaries in this story are noble and gentle and don’t mistreat the natives.

If my explanation isn’t clear, I’ll try to clear it up. Otherwise, good luck! This puzzle has bugged me for days.

2

Missed a rule: the canoe can only hold two people (although it is perfectly acceptable for it to only have one).

3

Easy! All six pile up in the canoe and cross at the same time. :slight_smile: (or did you forget some of the rules?)

4

http://www.family.loesch.net/oldpuzzles.html

Here’s a solution, but in this scenario, all of the missionaries can row and only one cannibal can row.

5

Trip 1 across: Head Cannibal, one cannibal.
Trip 1 back: Head Cannibal
Trip 2 across: Head Cannibal, one cannibal.
Trip 2 back: Head Cannibal.
Trip 3 across: Head Missionary, one missionary.
Trip 3 back: Head Missionary, one cannibal.
Trip 4 across: Head Missionary, Head Cannibal.
Trip 4 back: Head Missionary, one cannibal.
Trip 5 across: Head Missionary, one missionary.

Now the Head Cannibal can ferry his buddies over.