Suppose that the number of units of a good produced, z, is given by z = 20xy,

Question:

Suppose that the number of units of a good produced, z, is given by z = 20xy, where x is the number of machines working properly and y is the average number of work-hours per machine. Find the production for a week in which
(a) 12 machines are working properly and the average number of work-hours per machine is 30.
(b) 10 machines are working properly and the average number of work-hours per machine is 25.