The water level at a local pier rises and falls with the tide. Yesterday, the maximum depth of the water at the pier was 8 feet, and the minimum depth was 4 feet. High tide occurred at 12:00 am and low tide occurred at 12:20 pm. Which function models the depth, in feet, of the water at the pier yesterday, as a function of the time t in minutes past high tide?

Ascientist places 24 cells in a petri dish. she knows the cells grow at an exponential rate, doubling in number every hour. how long will it take (in hours) for there to be 1100 cells in the dish? time to 1100 cells: 5.51832530 hours how long will it take to reach 110 cells? time to 110 cells : 2.1963972 hours what is the average rate of change in the number of cells between 9 hours and 11 hours? average rate of change: cells per hour what is the instantaneous rate of change after 7 hours? instantaneous rate of change: cells per hour note: you can earn partial credit on this problem.