Students at one middle school are called to lunch by their grade level. To determine whether all students at the school liked to eat hamburgers, hotdogs, or pizza for lunch, the lunchroom manager surveyed the first 30 students that were in the lunchroom. What type of sample is this? Please Help

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.