Answer:
The total cost is represented by 
Step-by-step explanation:
We have been given-
Calvin paid $1.79 per pound of beans both times that he went shopping. This is a constant value.
He bought 4.05 pounds of beans the first time and 2.78 pounds the second time.
So, the total cost in dollars of the beans he bought is represented by:

This is because the standard rate is $1.79 per pound.
No mater how many pounds you buy, you will have to multiply that with standard rate of $1.79.