The average fixed cost at 4 units of output is Rs20. Average variable cost at 5 units of output is Rs40. Average cost of producing 5 units is

• Rs 20
• Rs40
•  Rs 56
• Rs 60

Dear Student

Fixed cost does not change with change in output . Average fixed cost for 4 units of output = Rs. 20 . So total fixed cost = Rs. 20 multiplied by 4 , that is , Rs. 80 . So average fixed cost at 5 units = Rs. 80 divided by 5 , that is , Rs. 16 . Then comes the question of average variable cost . Here it is Rs. 40 for 5 units . 
To calculate average cost of producing 5 units :
      Average cost = Average fixed cost + Average variable cost
or,  Average cost of producing 5 units = Rs. 16 + Rs. 40 = Rs. 56 .

Regards .