A company uses x hours of unskilled labour, and y hours of skilled labour, to produce F(x,y) = 60x2/3 y1/3 units of output. It currently employs 400 hours of unskilled labour and 50 hours of skilled labour. The company is planning to hire an additional 5 hours of skilled labout.
Use a linear approximation (degree one approximation) to decide by about how much the company can reduce its use of unskilled labour and keep its output at current level.