If AR is RS.40 per unit from sale of 3 unit of good and is RS.30per unit from the sale of 4 unit of good. Find the marginal revenue of 4th unit of good

Dear Student

Unit	Average revenue	Total Revenue (unit * quantity)
3	40	120
4	30	120

Marginal Revenue = Total revenue_n - Total revenue_n-1
Marginal Revenue = 120 -120
Marginal Revenue = 0
So MR for 4th unit is 0 as total revenue for 3rd and 4th unit is same

Regards