Complex sentence: Pérez Simón met Carlos Slim when they were both young men and they went into business in 1976 as partners in the Carso Group with Pérez Simón taking a minority 30% stake.
Split into simpler sentences: Pérez Simón met Carlos Slim when they were both young men. They went into business in 1976 as partners in the Carso Group with Pérez Simón taking a minority 30% stake.