The standard deviation of the sound levels from 20 randomly selected spots in our college was 4.1 dBA, while the standard deviation from another 24 randomly selected spots was 7.5 dBA. Set , then we should

Suppose that the price p, in dollars, and the number of sales, x, of a certain item follow the equation 4 p plus 4 x plus 2 pxequals56. suppose also that p and x are both functions of time, measured in days. find the rate at which x is changing when xequals2, pequals6, and startfraction dp over dt endfraction equals1.5.