Alex, Kara, and Susie are the only three people in a community. Alex is willing to pay $20 for the fifth unit of a public good; Kara, $15; and Susie, $25. Government should produce the fifth unit of the public good if the marginal cost is less than or equal to:

$60

Explanation:

Data provided in the question

Alex willing to pay = $20

Kara willing to pay = $15

Susie willing to pay = $25

So, by considering the above information, the fifth unit of the public good that the government should produced is

= Alex willing to pay + Kara willing to pay + Susie willing to pay

= $20+ $15 + $25

= $60

Basically we added the willing to pay of these three persons that are displayed above