Jessica gets 3 CDs for Christmas, but they are currently useless to her because she doesn’t have any CD player and she cannot return them for a refund (these 3 CDs are the only CDs she has). Her utility function is U(x, y, z) = x + f(y)z², where z is the number of CDs she has, y is the number of CD players she has, and x is the money she has to spend on other stuff. Let f(y) = 0 if y < 1 and f(y) = 6 otherwise. What is the maximum amount Jessica would be willing to pay for the CD player?

Consumer's preferences might be represented by the utility function u(x,y)=10x-x²+y. The consumer has income m=100 and the price of x is 4 and the price of y is 1. What is the consumer's utility gain from getting access to the market with x?

Tom’s utility function is U(x, y) = 4x + 3y. Tom has $180 to spend. The price of x is $4. Tom currently doesn’t consume any y. Tom has received an invitation to join a club devoted to the consumption of y. If he joins the club, Tom can get a discount on the purchase of y. If he belonged to the club, he could buy y for $2 per unit. How much is the most Tom would be willing to pay to join this club? Note that if he is indifferent about whether to join the club or not, he will join the club.

Suppose that Frank buys bananas (x) and oranges (y). His budget line was described by the equation y=30-2x. At a later time, his budget line could be described by the equation y=20-x. What is a possible explanation for the change between the earlier and the later budget line?

Willy likes playing football and computer games. Playing football for 20 minutes and Fortnite for 30 minutes makes him as satisfied as playing football for 50 minutes and Fortnite for 10 minutes. Suppose that he now plays Fortnite for 20 minutes, and his preferences are convex.

Given only this information about Willy's preferences, what is the theoretical maximum time he could spend playing football to be as well off as in the previous two situations? Please insert a numerical value only.

Which of the following statements about the marginal rate of substitution is correct?

Suppose that Amanda spends all of her income on blueberries and broccoli (she has just learned that it is the perfect diet for her brain). She can just afford 12 packs of blueberries and 6 broccolis per week. She could also use her entire income to purchase 8 packs of blueberries and 14 broccolis per week. The price of one broccoli is CZK 30. Calculate the price of one blueberries pack. Please, insert numerical value only.

Andy consumes goods x and y and his indifference curves are described by the formula y = k/(x+1) (higher values of k correspond to better indifference curves). Andy strictly prefers the bundle (x,y)=(9, 10) to

Willy has income m and consumes good x and good y that have initial prices p_x and p_y. Suppose that p_x doubles and p_y triples while income also doubles. On a graph showing the budget line with good x on the horizontal axis and good y on the vertical axis,

Johny likes grapefruits and pomelos. He is always willing to exchanges 6 grapefruits for 2 pomelos and vice versa. If we depict pomelos on the horizontal axis and grapefruits on the vertical axis, what is the slope of Johny's indifference curve? Please insert a numerical value only (use decimals instead of fractions if necessary). Don't forget to write the correct sign.