Lake Mead is the largest manmade reservoir in the United States. It has a surface area of 247 square miles. Lake Mead receives approximately 8.23 million acre-feet of water per year but operates at a deficit of 1.2 million acre-feet per year. Currently, it is only at 40% of its capacity. The evaporation rate is 9 feet per year, and the people in the region use 205 gallons per person per day. a. (10 points) The level of the lake is falling over time. It has not been full since 1983. Based on the numbers provided in the problem statement, calculate the drop of water level in feet per year. b. (8 points) Calculate how many people are using Lake Mead as a water source to achieve that drop level assuming that the people in the region are responsible for using 205 gallons per person per day.