Marginal revenue product is defined as the change in total revenue that results from the employment of an additional unit of a resource. A widget producer wishes to determine how the addition of pounds of rubber will affect its MRP and profits. See the table below, and answer the question.
Pounds of rubber Number of widgets Price of widgets ($)
(quantity of resource) (total product)
0 0 -
1 20 12
2 35 10
3 45 8
4 50 6
5 53 4
The marginal product of the 3rd pound of rubber is _______________.