She stayed in the hospital for 91 hours, because at 4:00pm there are 8 hours left in the day, so 8 hours go by and its july 8th, there are 3 days left until july 11th, there are 24 hours in a day,(3x24=72), then 11 hours go by until it's 11:00,(72+11=83). Then you add the 8 hours from before(83+8=91) Thats how you get the answer
She was in the hospital for 91 hours because july 7th 4pm-july 10th 4pm is three days(72 hrs) and then july 10th 4pm-july 11th 11am is 12 hours. 72+12=91
