A long haul semi truck driving on a highway. RichLegg/E+ via Getty Images In investing, nothing is guaranteed. However, buying great businesses at reasonable or discounted valuations works out more often than not over the long run. Of my picks in recent months, Cummins (NYSE:CMI) provides an example of this in action. When I last covered it with a buy rating in June, I thought its recent and upcoming product launches could reinvigorate growth. The A-rated balance sheet was another positive. Finally, the v ...