Today, you buy $120$ shares of MSFT at an average price of $$245\mathrm{.}6$ using a market order. At

the time of your order submission, the midpoint of the bid$-$ask spread for the stock is $$245.$

Two months later, you sell the $120$ shares at an average price of $$250$ using again a market

order, when the midpoint is $$251.$ Assume that the bid$-$ask spread of MSFT is constant and

equal to $$1.$

a$.$ What are your total implicit transaction costs on this trade $($in dollars$)?$ What fraction

of total implicit costs is price impact?

b$.$ What is the return in percent on your trade? What would have been the return on your

trade had you been able to trade at the midpoint?