This is an excerpt, pages 41-47, from George Gamow’s ONE TWO THREE . . . INFINITY: Facts and speculations of science. It was published by Viking Press in 1947 and reprinted by Mentor Books for the New American Library in 1953. This excerpt is from the 1960 Ninth Printing of the Mentor Books edition. Subsequently (and as recently as 1988) it was re-published by Dover Books and is still available from them.
On page 41 a discussion of complex numbers begins. After Figure 10 on page 44, the discussion of the Treasure Problem begins and the problem, with a solution using complex numbers, is presented pp 44-47.