4. Suppose that Leah's company is characterised by the following Cobb- Douglas production function z = f(x, y) = 50x1/21/1/2 where r is the number of units of labour, y is the number of units of capital and z is the units of production. Each unit of labour costs $25 in wages and each unit of capital is $5. Leah's company is also subject to a limit of $75,000 for the total cost of labour and capital. Find the number of units of labour and the number of units of capital that will allow Leah's company to maximise production and use this information to calculate the z for which production is maximised