A mixture consists of 10 L at $2/L and 20 L at $3/L. What is the average cost per liter of the mixture?

To determine the average cost per liter of the mixture, we first calculate the total cost of each component of the mixture.

For the first part of the mixture:

• Volume: 10 liters

• Cost per liter: $2

• Total cost: ( 10 , \text{L} \times 2 , \frac{\text{dollars}}{\text{L}} = 20 , \text{dollars} )

For the second part of the mixture:

• Volume: 20 liters

• Cost per liter: $3

• Total cost: ( 20 , \text{L} \times 3 , \frac{\text{dollars}}{\text{L}} = 60 , \text{dollars} )

Next, we combine the total costs of both parts:

• Total cost of the mixture: ( 20 , \text{dollars} + 60 , \text{dollars} = 80 , \text{dollars} )

Now, we find the total volume of the mixture:

• Total volume: ( 10 , \text{L} + 20 , \text{L}