The way to solve the problem is as follows:

Variable cost = unit variable cost * quantity = 40 * 20 = 8 million yuan.

Total cost = fixed cost+variable cost = 300+800 = 1 1 ten thousand yuan.

Fixed cost (also known as fixed cost) refers to the cost that the total cost can remain unchanged within a certain period of time and within a certain range of business volume, regardless of the increase or decrease of business volume.

Variable cost, also known as variable cost, refers to the cost items that change with the change of output in the total cost, mainly the value of production factors such as raw materials, fuel and power; When the output increases in a certain period of time, the consumption of raw materials, fuel and power will also increase in proportion, and the costs incurred will also increase in proportion, so it is called variable cost. Variable cost equals total cost minus fixed cost.