366 Answersfigure I, as shown. Now take the second column, and you will find that there
are three ways of going to the second point from the bottom, five ways to the
next above, seven to the next, and so on, continually adding two. The same
applies to the second row from the bottom. Write in these numbers. Then the
central point of all can be reached in thirteen ways, because we can enter it
either from the point below that can be reached in five ways, from the point
to the left that can also be reached in five ways, or from the diagonal point below
that can be reached in three ways, making together thirteen. So all we have
to do is to write in turn at every point the sum of those three numbers from
which it can be immediately reached. We thus find that the total number
of different routes from H to C is 321.
- THE SUBMARINE NET
The illustration will show the best way of cutting the net. It will be seen that
eight cuts are made from A to B, dividing the net into two parts.