ECON 1001 ABIntroduction to

Economics IDr. Ka-fu WONG

Fifth week of tutorial sessions

KKL 925, K812, KKL 106Clifford CHAN

KKL 1109givencana@yahoo.ca

Covered and to be covered

Covered last week Dr. Wong finished up to slide #26 of kf005.ppt You should have at least read up to Chapter 5 Demand: The

Benefit Side of the Market, and the Appendix If not, please press hard on it. Start reading Chapter 6 Your first Economics Naturalist writing assignment is due this Friday

October 12.

To be covered in the tutorial sessions this week Problems in chapter 5: #1, #3, #5, #7, #8 and #9 You are advised to work on the even ones as well

Problem #1, Chapter 5

In which type of restaurant do you expect the service to be more prompt and courteous: an expensive gourmet restaurant or an inexpensive diner? Explain.

Solution to Problem #1 (1)

Refer to chapter 1 We discussed that the amount you are willing to spend on a

certain product reveals the value or the benefit of the product If you are rational and are willing to pay $800 for an admission

ticket to watch a concert, the value or benefit of the concert must be at least $800

In the question, two options are given: an expensive gourmet restaurant and an inexpensive diner

Both the restaurant and the diner are actually businesses selling food and services

Solution to Problem #1 (2)

In of terms of Economics goods, is “food” a normal good or an inferior good? Food is both a necessity and a normal good. If your income incre

ases, you will probably increase your consumption in food or increase your consumption in expensive food like premium beef and seafood

In of terms of Economics goods, is “service” a normal good or an inferior good? Service is also a normal good. If your income increases, you will

probably spend more on service or spend more on expensive service like hiring a in-house maid to do all the housework or hiring an professional accountant to look over your wealth management

Solution to Problem #1 (3)

Thus, “Willingness to pay for FOOD”, and that for SERVICE are increasing functions with income

Expensive gourmet restaurants like those in ifc or in luxurious hotels target on diners who earn higher incomes

Inexpensive diners like those on campus target on diners who earn lower incomes

Solution to Problem #1 (4)

To attract diners earning higher incomes and charge them a higher price, expensive gourmet restaurants provide high quality of food as well as high quality of service

To attract diners earning lower incomes and charge them a lower price, inexpensive diners provide low quality of food as well as low quality of service (self-serve on campus)

Problem #3, Chapter 5

Martha’s current marginal utility from consuming orange juice is 75 utils per ounce and her marginal utility from consuming coffee is 50 utils per ounce. If orange juice costs 25 cents per ounce and coffee costs 20 cents per ounce, is Martha maximizing her total utility from the two beverages? If so, explain how you know. If not, how should she rearrange her spending?

Solution to Problem #3 (1)

Notion of marginal utility The extra (additional) satisfaction one derives from one’s

consumption activities Thus, we can draw a parallel line between marginal utility and

marginal benefit

Recall from chapter 1 and chapter 2 Rule of allocating resources For a resource that is perfectly divisible, and for activities for

which the marginal product of the resource is not always higher in one than in the others, the rule is: Allocate the resource so that its marginal benefit is the same

in every activity

Solution to Problem #3 (2)

Since the marginal utility from consuming (75 utils) orange juice is not the same as the marginal utility from consuming coffee (50 utils), Martha has not maximized total utility from drinking orange juice and coffee

Alternatively, we can take a different approach to the problem as follows When the quantity of each good can be varied continuously, we

can solve this problem by applying the Rational Spending Rule: Spending should be allocated across goods so that the

marginal utility per dollar is the same for each good

Solution to Problem #3 (3)

Currently, The marginal utility from drinking orange juice per dollar

= Marginal utility from consuming orange juice / Price per ounce = 75 utils / $0.25 = 300 utils per dollar from her last dollar spent on orange juice

The marginal utility from drinking coffee per dollar = Marginal utility from consuming coffee / Price per ounce = 50 utils / $0.20 = 250 utils per dollar from her last dollar spent on coffee

Solution to Problem #3 (4)

As the marginal utilities from consuming orange juice and coffee are not the same, Martha has not maximized her total utility from drinking orange juice and coffee

To improve her total utility from consuming orange juice and coffee, Martha should drink more orange juice and less coffee

Why? Drinking more orange juice will drive down the marginal

utility from consuming orange juice per dollar Drinking less coffee will drive up the marginal utility from

consuming coffee per dollar Note utility is a decreasing function with consumption

Problem #5, Chapter 5

Sue gets a total of 20 utils per week from her consumption of pizza and a total of 40 utils per week from her consumption of yogurt. The price of pizza is $1 per slice, the price of yogurt is $1 per cup, and she consumes 10 slices of pizza and 20 cups of yogurt each week.

True and false: Sue is consuming the optimal combinatio

n of pizza and yogurt.

Solution to Problem #5 (1)

Insufficient information!!! To prove whether Ann is consuming an optimal combinat

ion of pizza and yogurt, we need to check whether the Rational Spending Rule holds in her case

Rational Spending Rule holds if the marginal utilities per dollar from the consumptive activities are the same

Unlike Problem #3 in which marginal utilities of consumptive activities are given, Problem #5 provides total utilities of consumptive activities

Thus, we can only come out with the average utilities per dollar from consuming pizza and yogurt

Problem #7, Chapter 5

For the demand curve shown, find the total amount of consumer surplus that results in the gasoline market if gasoline sells for $2 per gallon

1,000s of gallons/yr

10

100P

rice

($/g

allo

n)80

2

Solution to Problem #7 (1)

Reservation price refers to the maximum price that one will pay to buy a certain product or service

Consumer’s surplus refers to the difference between a buyer’s reservation price for a product and the price actually paid

For example, I am willing to pay $30 for a Ham and cheese source sandwich sold at Starbucks for which it is sold for only $20 My maximum willingness to pay (reservation price) is $30 The actual price I have to pay is $20 Consumer surplus = $30 - $20 = $10

Solution to Problem #7 (2)

If we keep calculating the consumer surplus in such a way that one’s reservation price minus the actual market price of gasoline ($2), we will get a total consumer surplus that is equal to the area under the demand curve but above the actual price ($2)

Consumer’s surplus when the gasoline is $2 per gallon = ($10-$2) * 800,000 gallons * (1/2) = $320,000

Consumer’s surplus when the gasoline is $0 per gallon = ($10-$0) * 100,000 gallons * (1/2) = $500,000

Solution to Problem #7 (3)

Consumer’s surplus The area under the demand curve but above the

actual market price It is a triangle under a linear demand curve but

above the actual market price

Problem #8 (1), Chapter 5

Tom has a weekly allowance of $24, all of which he spends on pizza and movie rentals, whose prices are $6 per slice and $3 per rental, respectively. If slices of pizza and movie rentals are available only in whole-number amounts, list all possible combinations of the two goods that Tom can produce each week with his allowance

Problem #8 (2), Chapter 5

Pizza / week Utils / week from pizza

Movie rentals / week

Utils / week from movie rentals

0 0 0 0

1 20 1 40

2 38 2 46

3 54 3 50

4 68 4 54

5 80 5 56

6 90 6 57

7 98 7 57

8 104 8 57

Solution to Problem #8 (1)

Tom has a weekly allowance of $24 which he can spent on pizza and movie rentals

$6 for a slice of pizza $3 for a movie rental

Possible combinations of pizza and rentals Total $

0 slices of pizza, 8 movie rentals $24

1 slice of pizza, 6 movie rentals $24

2 slices of pizza, 4 movie rentals $24

3 slices of pizza, 2 movie rentals $24

4 slices of pizza, 0 movie rental $24

Problem #9, Chapter 5

Refer to Problem #8. Tom’s total utility is the sum of the utility he derives from pizza and movie rentals. If these utilities vary with the amounts consumed as shown in the table, and pizzas and movie rentals are again consumable only in whole-number amounts, how many pizzas and how many movie rentals should Tom consume each week?

Solution to Problem #9 (1) To find the optimal combination of consumption in pizzas and

movie rentals, we need to calculate the total utility of each possible combination of consumption on the two goods

Possible combinations of pizza and movie rentals

Total $ per

week

Total utility per week

0 slices of pizza, 8 movie rentals $24 0 + 57 = 57

1 slice of pizza, 6 movie rentals $24 20 + 57 = 77

2 slices of pizza, 4 movie rentals $24 38 + 54 = 92

3 slices of pizza, 2 movie rentals $24 54 + 46 = 100

4 slices of pizza, 0 movie rental $24 68 + 0 = 68

Solution to Problem #9 (2)

Recall marginal utility The extra (additional) satisfaction one derives from one’s consu

mption activities

The higher level of utility, the higher level of satisfaction

Based on the above table, Tom should consume 3 slices of pizza and 2 movie rentals per week, as this is the optimal combination yielding the maximum total utility (100)

The end

Thanks for coming!

Good luck on your writing assignment!!!