Answer:

Explanation:
Let us assume that the total cost of the grapes = x $.
Given that it costs 1.55 $ for one pound. We are asked to determine how much it would cost for 3.5 pounds.
note that for one pound you pay 1.55 so how much should you pay for 3.5 pounds? Clearly, the cost increases with the increase in weight of the item.
This is equal to


Hence, the answer.