QUESTION $3$

a$)$ Suppose that the demand for a product is given by $2p^{2}q=5000+1000p^2.$ Find the elasticity when $P=RM50$ and $q=501$ where $p$ is in Ringgit and $q$ is the number of units.

$(4$ Marks$)$

b$)$ Suppose that a company's sales volume $y($in Ringgit$)$ is related to its advertising expenditures $x($in Ringgit$)$ according to $xy-72x+10y=0.$ Find the rate of change of sales volume, with respect to advertising expenditures when $x=RM10.$

$(4$ Marks$)$