Bunuel wrote:
Company R's annual profit has increased by a constant amount each calendar year since 1985. What was Company R's annual profit in 1991?
(1) In 1985 Company R's annual profit was $212,000; in 1989 Company R's annual profit was $242,000.
(2) Company R's annual profit has increased by $7,500 each year since 1985.
Question stem: Company R's annual profit has
increased by a constant amount each calendar year since 1985
It means that the profit in each subsequent year since 1985 is in an AP.
Statement 1:In 1985 Company R's annual profit was $212,000; in 1989 Company R's annual profit was $242,000
We can compute the common difference of the progression and add two more such common differences to compute the value for 1991.
We will get a unique answer.
That will suffice. We need not compute the value as it is a DS question.
However, this is the value. The annual increase in profit = (profit in 1989 - profit in 1985)/4 = (242,000 - 212,000)/4 = 7500.
So, profit in 1991 = Profit in 1989 + 2 * common difference = 242,000 + 2*7500 = $257,000
Statement 1 is sufficient.
Statement 2: Company R's annual profit has increased by $7,500 each year since 1985
We do not know the profit in 1985 or any of the years between 1985 and 1991 to find the answer.
Statement 2 is NOT sufficient.
Choice A.