There are 19 women. The number of pairs ww is 7 and the one of wm is 12. Considering now the left neighbors of the women, there must also be 12 pairs mw, which is 75% of the men. Thus there are 16 men and 35 people altogether.

But how can u say there r 17 women? What about those who have men on their left?

ryan, at least you could copy the correct figure: it's $19$ women, not $17$. As for your question, those women who have men on their left are also counted in the $19$, since they must have someone on their right, and the $19$ counts both cases - $7$ when the person is a woman, and $12$ when the person is a man.