Please reason step by step, and put your final answer within \boxed{}.
Cary is 72 inches tall. Her younger brother Bill is 80% of her height, and her younger sister Jan is 5 inches taller than Bill. Their youngest brother, Tim, is 4 inches shorter than the average height between Bill and Jan. Lastly, their cousin Sara is 1.2 times taller than the mean average height of all four siblings. How tall are Bill, Jan, Tim, and Sara?
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