Answer:
a) $140.
Step-by-step explanation:
To calculate profit, we can use following formula:
Sales in $ - Cost of Goods Sold = Gross Profit.
As we need to know how much does the profit increase as a result, we calculate with 20 units and not with total sales.
Then, to give the answer to this question, sales are 20 units.
(20*$15)-(20*$8)=$140