Complex sentence: By 1948, Mrs. Doheny had dealt with the fraternity for long enough and offered $75,000 to purchase the house that the fraternity bought eight years earlier for $20,000.
Split into simpler sentences: By 1948, Mrs. Doheny had dealt with the fraternity for long enough. So she offered $75,000 to purchase the house that the fraternity bought eight years earlier for $20,000.