Last month, a certain manufacturer sold a total of 1,000 unites of its two products, A and B. The selling price of each unit of product A was $1,500, and the selling price of each unit of product B was $2,000. How many units of product A did the manufacturer sell last month?
(1) Last month, the manufacturer's total revenue from the sale of units of products A and B was $1,600,000.
(2) Last month, the manufacturer's revenue from the sale of units of products A was 3 times the manufacturer's revenue from the sale of units of product B.