In a srs of 80 teenagers, the average number of text messages received per day is found to 50. if the standard deviation of number of texts received is known to be σ = 12, find the 95% confidence interval for the number of text messages received.

Solve the following pair of equations for x and y: ax/b_ by /a= a +b; ax - by = 2ab

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.

Marquise has 200 meters of fencing to build a rectangular garden. the garden's area (in square meters) as a function of the garden's width w w (in meters) is modeled by: a ( w ) = − w 2 + 1 0 0 w a(w)=−w 2 +100w what side width will produce the maximum garden area? meters