How far will atmospheric pressure (23.6 psi) push up a column of mercury? (The density of Mercury is 849 pounds per cubic foot.)

It took alice 5 5/6 hours to drive to her grandparents' house for . on the way home, she ran into traffic and it took her 7 3/8 hours. how much longer did the return trip take? write your answer as a proper fraction or mixed number in simplest form. the trip home took __hours longer. ?