The stock will appreciate, that is a given. but you are very wrong on your analysis. Microsoft needs a steady revenue source via advertising on an online portal. google, which controls almost 70% of the search market, makes billions of dollars by receiving the kind of advertising microsoft is looking for. in order to gain any kind of momentum or footing in the online search market, and try to kickstart a revenue stream and compete with google, they will need to obtain yahoo's search service.
your prediction of 30 dollars is way off the mark. the reason is because microsoft will not offer money for the stock of yahoo because it is not purchasing yahoo. it is attempting to purchase yahoo search. in fact, since Icahn is now on the board and Yang is still CEO, it is less likely than ever that yahoo would agree to an outright purchase.
additionally, once yahoo (read if yahoo) would sell its search than in the long term, they are a dying company. The ad revenue sharing deal with google will be off and they no longer would make money on their search. where would that stream of income come from?
so while the stock may appreciate a bit, your analysis is incorrect