The following table shows actual and projected worldwide annual sales and average selling prices of a certain type of smartphone in 2020 and 2024. q(p) Year = 2020 Selling Price ($) Sales (millions) 400 600 2024 350 (a) Use the data to obtain a linear demand function for this type of cell phone. (Let p be the price, and let q be the demand). 950 X Use your demand equation to predict sales (in millions) if the price is lowered to $300. million phones (b) Fill in the blank. For every $1 increase in price, sales of this type of cell phone decrease by million units.