Solution for ›Hexagon walk‹

There are eight ways of combining the numbers to sum up to 16:

1 + 2 + 3 + 4 + 6

1 + 2 + 6 + 7

1 + 3 + 5 + 7

1 + 4 + 5 + 6

2 + 3 + 4 + 7

2 + 3 + 5 + 6

3 + 6 + 7

4 + 5 + 7

Only one of them will work.