To find the constant of proportionality from the given data, you can determine the ratio of pages read to time (in hours).
From the provided data:
- (12 hours, 15 pages) → Ratio: \( \frac{15}{12} = \frac{5}{4} \)
- (1 hour, 30 pages) → Ratio: \( \frac{30}{1} = 30 \)
- (112 hours, 45 pages) → Ratio: \( \frac{45}{112} \approx 0.4018 \)
- (2 hours, 60 pages) → Ratio: \( \frac{60}{2} = 30 \)
Now, to find the constant of proportionality for Ruth based on her reading speed of 15 pages in 30 minutes, we first convert 30 minutes to hours: \( 30 \text{ minutes} = 0.5 \text{ hours} \).
So, the ratio for Ruth is:
- (0.5 hours, 15 pages) → Ratio: \( \frac{15}{0.5} = 30 \)
Now, we look for the option which matches a ratio of 30:
- (1, 30)
- (15, 12)
- (112, 30)
- (2, 60)
The pair (2, 60) corresponds to a reading of 60 pages in 2 hours, which simplifies to 30 pages per hour, aligning with our constant of proportionality.
Thus, the answer is: (2, 60).