Question

A group of 3 explorers travelled through the new Guinea rain forests with 3 Marind-Anim guides. Their inflatable dinghy could only take 2 people at a time and only one of the explorers and one guide could successfully operate it. Once the explorers realised that the Marind-Anim were renowned head hunters they were not willing to ever be outnumbered by them. In spite of these difficulties they worked out a way to negotiate each river. What is the smallest number of crossings needed to get the party safely across a river?

Answer 1

Answer:

Hello,

Step-by-step explanation:

Let's assume A,B,C the 3 explorers and X,Y,Z the 3 guides.

Only A and X can operate the boat.

$\begin{array}{|c|c|c|}border\ 1 &boat&border\ 2\\ABCXYZ&-&-\\BCYZ&AX&-\\BCYZ&A&X\\BCY&AZ&X\\BCY&A&XZ\\CY&AB&XZ\\CY&X&ABZ\\Y&CX&ABZ\\Y&X&ABCZ\\-&XY&ABCZ\\-&-&ABCXYZ\\\end{array}$

I hope you will understand the travels