Answer to the October 18, 1999 Problem of the Week

Three men, traveling with their wives, came to a river which they wanted to cross. The one available boat would accomodate only two people.

Since the husbands were very jealous, no woman could be with a man unless her own husband was present.

Under these severe handicaps, how can they get across the river using the one boat?

In sending your solution, perhaps it would be a good idea to refer to the three couples as
A, a, B, b, C, and c, where the capital letters refer to husbands and lower case letters refer to their wives (or vice versa!).

Solution to the Problem:

Mrs. B and Mrs. C cross, and Mrs. B returns with the boat.
Mrs. B and Mrs. A cross, and Mrs. A returns with the boat.
Mr. B and Mr. C cross, and Mr. and Mrs. B return with the boat.
Mr. B and Mr. A cross, and Mrs. C returns with the boat.
Mrs. B and Mrs. C cross, and Mr. A returns with the boat to pick up his wife.

A B C a	--- b c --->
A B C a	<--- b ---	c
A B C	--- b a --->	c
A B C	<--- a ---	b c
A a	--- B C --->	b c
A a	<--- B b ---	C c
a b	--- A B --->	C c
a b	<--- c ---	A B C
a	--- b c --->	A B C
a	<--- A ---	B C b c
	--- A a --->	B C b c

Correctly solved by:

1. Tom Marino	Winchester, VA
2. Liz Cotter	Oak Hill, VA
3. Richard Mocarski	Winchester, VA
4. Ankit Garg	Fremont, CA