Answer:The marginal cost of fourth unit is $589
Explanation:The marginal cost of a good is defined as the cost of producing an additional one unit which increases the total cost of such good. Therefore we can say that;
Marginal cost=Total cost at 4 units - total cost at (4-1) units
=total cost of the 4 units - total cost of the three units
=3,087 -2,498
=$589
Also using the formulae;
Marginal cost = Change in cost / change in quantity
= 3,087 -2,498/4-3 =589/1= $589
The marginal cost of fourth unit is $589