Econ 302: Solutions for Questions
about the Budget
Set
Question 1:

-
The budget constraint is given by
4x1+10x2=<200.
- Thus,
the budget line is given by
4x1+10x2=200. The intercepts are (50,0) and
(0,20).
The slope is -p1/p2=4/10=0.4. (dark
line in the graph).
- The budget set is the area underneath the budget line (red + yellow
area excluding the yellow triangle on the top).
- The new
budget line is
10x1+10x2=300.
- The intercepts are (30,0) and
(0,30).
The slope is -p1/p2=-1 (grey line in
the graph).
- The new budget set is the yellow area in the graph.
Question 2:
The budget line is given by
2x1+4x2+10x3=49. Since
x1=2, this reduces to
4x2+10x3=45. Because the consumer purchases
twice as many units of good 2 than of good 3, the equation
x2=2x3 must hold. Thus, substitute
2x3 for x2 in the equation
4x2+10x3=45 to get
x3=2.5. Therefore,
x2=5. Consequently, the consumption bundle is
(2,5,2.5).
Question 3:
- If consumption of good 1 is 0 then all money is available for
consumption of other goods. Thus, the vertical intercept is (0,20).
- Purchasing three units of good 1 costs 6 Dollars. Thus, 14
Dollars are left, and we get (3,14).
- Every additional unit costs 1 Dollar. If the remaining 14
Dollars are spent on cereal, 14 boxes (in addition to the 3) can be
purchased. Thus, the horizontal intercept is (17,0).
- The budget set is indicated by the yellow area. The budget line
is the blue line in the graph.
- The slopes are -2 and -1, respectively.
Question 4:
- Similar to the previous question, the vertical intercept is
(0,2000).
- If the insurance covers 80% of the cost, then this means that per
unit, the insurance company pays 80 Dollars and the consumer pays 20
Dollars. The company only pays up to 1000 Dollars. Thus, we must find
the value x1 for which
80x1=1000. Therefore x1=12.5.
-
Up to x1=12.5 the consumer faces a price of 20 Dollars per
unit. Purchasing 12.5 units therefore costs 250 Dollars. This reduces
consumption of other goods (measured in Dollars) from 2000 to 1750.
Therefore we get (12.5,1750).
- If x1>12.5 the consumer faces a price of 100 Dollars
per units. Since there are 1750 Dollars left, 17.5 additional units
can be purchased. Thus, the intercept is (30,0).
- The budget set is indicated by the yellow area. The budget line
is the blue line in the graph.
- The slopes are -20 and -100, respectively.
- The graph can be seen below.

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