The amount of water is directly proportional to the number of cups of rice. The coordinate (1/2, 1) is on the graph of this proportional relationship. Identify another point on the graph

A. (2, 6)
B. (2/3, 4)
C. (1/4, 2)
D. (3/2, 3)

1 answer

Given that the amount of water is directly proportional to the number of cups of rice, we can express this relationship mathematically as:

\[ W = kR \]

where \( W \) is the amount of water, \( R \) is the number of cups of rice, and \( k \) is the constant of proportionality.

From the point \( \left(\frac{1}{2}, 1\right) \), we can substitute into the equation to find \( k \):

\[ 1 = k \cdot \frac{1}{2} \] \[ k = 2 \]

Now that we have \( k \), we can write the equation for the proportionality:

\[ W = 2R \]

To find another point on this graph, we can check each of the given options by plugging the \( R \) values into the equation \( W = 2R \) and see if they provide a corresponding \( W \) value.

A. For \( R = 2 \): \[ W = 2 \cdot 2 = 4 \] Resulting point: \( (2, 4) \) (not included in the options)

B. For \( R = \frac{2}{3} \): \[ W = 2 \cdot \frac{2}{3} = \frac{4}{3} \] Resulting point: \( \left(\frac{2}{3}, \frac{4}{3}\right) \) (not included in the options)

C. For \( R = \frac{1}{4} \): \[ W = 2 \cdot \frac{1}{4} = \frac{1}{2} \] Resulting point: \( \left(\frac{1}{4}, \frac{1}{2}\right) \) (not included in the options)

D. For \( R = \frac{3}{2} \): \[ W = 2 \cdot \frac{3}{2} = 3 \] Resulting point: \( \left(\frac{3}{2}, 3\right) \) (this matches option D)

Thus, the correct answer is:

D. \( \left(\frac{3}{2}, 3\right) \)