SUPPLY AND DEMAND CURVES
Qs = -100 + 25 P		Qd = 300 - 15 P		Proper Supply and Demand Curves
-50	25	300	-15	2	0.04	20	-0.06667
P	Qs	Qd		Q	Ps	Pd
0	-50	300		0	2	20.00
1	-25	285		10	2.4	19.33
2	0	270		20	2.8	18.67
3	25	255		30	3.2	18.00
4	50	240		40	3.6	17.33
5	75	225		50	4	16.67
6	100	210		60	4.4	16.00
7	125	195		70	4.8	15.33
8	150	180		80	5.2	14.67
9	175	165		90	5.6	14.00
10	200	150	Equilibrium	100	6	13.33
11	225	135		110	6.4	12.67
12	250	120		120	6.8	12.00
13	275	105		130	7.2	11.33
14	300	90		140	7.6	10.67
15	325	75		150	8	10.00	Equilibrium
16	350	60		160	8.4	9.33
17	375	45		170	8.8	8.67
18	400	30		180	9.2	8.00
19	425	15		190	9.6	7.33
20	450	0
Homework 1. To Use Excel to Draw Pseudo Supply and Demand Curves
Objective: To have the student familiarize himself with Excel to create supply and
demand series and to graph them using P as the horizontal axis.
Tasks:
1. Enter the parameters of the two curves into cells on the spreadsheet. The
curves are given as Qs = -100 + 25 P; Qd = 300 - 15 P.
In column A you will create a price series from 0 to 20 dollars. In columns B and
C you will generate Qs and Qd, respectively. I would suggest you refer to the cells
containing the parameters, as this allows one to change the graph by merely
changing the entry in a cell.
2. Now graph the two curves using Chart Wizard. Start by highlighting the spread-
sheet, including the titles row and the three columns. Then follow the directions,
using the first column as the x-axis and first row as the titles.
3. When this is done print out the spreadsheet data and the graph. Save the sheet,
as we will do more with it later to make it look nicer.
To make a proper supply and demand graph, the price must be on the vertical axis
and quantity on the horizontal axis. You will first have to "rotate" the axes by calculating
the new intercept and slope parameters for each curve. You may do this externally, or
by using cell formulas. Note that if a4 contains the old intercept for the supply curve and
cell a5 has the old slope, then the new intercept is given by (-a4/b4) and the new slope
by