A graphing calculator may be used for the following problem. On a given workday, the rate. in tons per hour, at which unprocessed ore arrives at a renery is modeled by 00:) = 20 + 10 cos (g), where t is measured in hours and 0 5 ts 10. Atthe beginning of the workday. t= 0, the refinery has 100 tons of unprocessed ore. During the hours of operation, the refinery processes ore at a constant rate of 25 tons per hour. a) Find 0T4). Using correct units. interpret your answer in the context of the problem. b) How much total are has been processed by the renery after the plant has been open for 3 hours? c) Is the amount of unprocessed are at the renery increasing or decreasing at time t= 4 hours? Show the work that leads to your answer. :1) Determine the time at which the total rate of ore at the renery is neither increasing nor decreasing? Justify your