(Excel) The supply and demand functions of a good are given by
$$
\begin{aligned}
&P=-Q_{\mathrm{D}}+240 \\
&P=60+2 Q_{\mathrm{s}}
\end{aligned}
$$
where \(P, Q_{D}\) and \(Q_{5}\) denote price, quantity demanded and quantity
supplied, respectively. Sketch graphs of both functions on the same diagram,
on the range \(0 \leq Q \leq 80\) and hence find the equilibrium price. The
government now imposes a fixed tax, \(\$ 60\), on each good. Draw the new supply
equation on the same diagram and hence find the new equilibrium price. What
fraction of the \(\$ 60\) tax is paid by the consumer?
Consider replacing the demand function by the more general equation
$$
P=-k Q_{\mathrm{D}}+240
$$
By repeating the calculations above, find the fraction of the tax paid by the
consumer for the case when \(k\) is
(a) 2
(b) 3
(c) 4
State the connection between this fraction and the value of \(k\). Use this
connection to predict how much tax is paid by the consumer when \(k=6\).