how do you find the regtangulr patch?

9. WANEFMAC7 12.2.054. The number of cell phone subscribers in a country in the years 2000-2005 was projected to follow the equation N(t) = 39t + 68 million subscribers in year t (t = 0 represents January 2000). The average annual revenue per cell phone user was $350 in 2000. If we assume that due to competition the revenue per cell phone user decreases continuously at an annual rate of 20%, we can model the annual revenue as R(t) = 350(39: + 68)e_'2t million dollars. (a) Determine when to the nearest 0.1 year the revenue was projected to peak. (Submit your answer in terms of t.) l W (b) Determine the revenue, to the nearest $1 million, at that time. $ million -/10 points WANEFMAC7 12.2.051. My Notes A postal service will accept packages only if the length plus girth is no more than 72 inches. (See the figure.) Assuming that the front face of the package (as shown in the figure) is square, what is the largest volume package that the postal service will accept? in 3 Length GirthAssume that it costs a company approximately C(x) = 576,000 + 160x + 0.001x2 dollars to manufacture x units of a device in an hour at one of their manufacturing centers. How many devices should be manufactured each hour to minimize average cost? units What is the resulting average cost of a device? $ Q How does the average cost compare with the marginal cost at the optimal production level? Find how much they differ. $ I would like to create a rectangular vegetable patch. The fencing for the east and west sides costs $4 per foot, and the fencing for the north and south sides costs only $2 per foot. I have a budget of $176 for the project. What are the dimensions of the vegetable patch with the largest area I can enclose? HINT [See Example 2.] north and south sides 12 x ft east and west sides 24 X ft