if the mean is 70 minutes, then 90 minutes is 2 standard deviations above 70. if you look at the bell curve i drew, the percent of exams that took over 90 minutes is 2.5%
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<em><u>A </u></em><em><u>.</u></em> A balloon rose to a height of 605 feet above the ground. It then dropped 500 feet and then dropped another 105 feet.
