uppose a public good that is worth $1 billion is not produced by the market, and so the government provides it, but at a cost of $3 billion. This attempt to correct a market failure has:

the assumption the narrator makes in this excerpt is that the messages he heards were going to hurt the narrator's mom; the narrator just springs in to action. the narrator doesn't specify in this excerpt why he believes that the messages present a problem that requires protection.

answer: marginal utility of the fourth brownie is 0.

explanation: marginal utility is the addtional utility gained from the consumption of one more unit of a good. it is given by,

so, marginal utility at the 4th unit will be given by

since, the values are not given here, you can simply find marginal utility at fourth unit by subtracting total utility at 3rd unit from total utility at 4th unit.