Abi grows millet on two fields in Nigeria, his home country. He can work for at most 3000 hours on both fields. The North Field is more fertile. Figure DD shows the hours he will work on his North Field on the horizontal axis, from left to right. Whatever is left over he will work on the South Field. MP1 is marginal productivity on the North Field, and MP2 on the south field.
The principles used in this problem could also be applied to