Question $3[22]$

$3\mathrm{.}1$ The South African Department of Agriculture is interested in analysing the domestic market for maize. The chief economist of the Department of Agriculture estimated the following equations for the demand and supply curves of maize:

The demand for maize: $Qd=300-2P+41$

The supply of maize: $,$ Qs $=3P-50$

where I is the average income measured in thousands of rands.

$3\mathrm{.}1\mathrm{.}1$ If $I=25,$ what is the market$-$clearing price and quantity for maize?

$3\mathrm{.}1\mathrm{.}2$ If $I=50,$ what is the market$-$clearing price and quantity for maize?

$3\mathrm{.}1\mathrm{.}3$ Draw a graph to illustrate your answers to questions $3\mathrm{.}1\mathrm{.}1$ and $3\mathrm{.}1\mathrm{.}2.$

$3\mathrm{.}2$ The supply of beef is considerably reduced by multiple seasons of severe drought which caused consumers to turn to pork as a substitute for beef. How would yol explain this change in the beef market in "supply$-$and$-$demand" terms?

$3\mathrm{.}3$ In December, both the price of Christmas trees and the number of trees that are s will rise. Is this occurrence a violation of the law of demand? Explain your answer.