Fish181
Economists work with supply and demand curves that show the price P of goods as a function of the quantity Q of those goods supplied or demanded. For a certain product, the supply curve is \(P = aQ + b\) and the demand curve is \(P = \frac{k}{Q}\), where \(a\), \(b\), and \(k\) are nonzero constants. The point at which these curves intersect in the (\(Q, P\)) coordinate plane is referred to as the equilibrium point, and for this product the equilibrium point is (10,5). For this product, what are the values of \(a\), \(b\), and \(k\)?
(1) The point (8,1) is on the supply curve.
(2) The point (25,2) is on the demand curve.
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
Supply Curve = \(P = aQ + b\)
Demand Curve = \(P = \frac{k}{Q}\)
The point at which these curves intersect in the (\(Q, P\)) coordinate plane is referred to as the equilibrium point, and for this product the equilibrium point is (10,5)
Inference: Point
(10,5) lies on the demand and supply curves.
From the equation of the supply curve ⇒ \(5 = 10a + b\)
From the equation of the demand curve ⇒ \(5 = \frac{k}{10}\) ⇒ k = 50
Question: For this product, what are the values of \(a\), \(b\), and \(k\)
We already have the value of k, we need to find the value of \(a\) and \(b\)
Statement 1(1) The point (8,1) is on the supply curve.
As point (8,1) lies on the supply curve, the point should satisfy the supply curve equation.
\(1 = 8a + b\)
From the question premise, we know that \(5 = 10a + b\)
Using both equations we can find the value of \(a\) and \(b\).
This statement alone is sufficient to find the value of \(a\), \(b\), and \(k\). We can eliminate B, C, and E.
Statement 2(2) The point (25,2) is on the demand curve.
As point (25,2) lies on the demand curve, the point should satisfy the demand curve equation.
\(2 = \frac{k}{25}\)
\(k = 50\)
We already know this information from the question premise, hence the statement doesn't provide any new details. The statement alone is not sufficient to find the value of \(a\) and \(b\).
Eliminate D.
Option A