To determine who spent more time writing per problem, we need to calculate the unit rate of minutes spent per problem for both Sonia and Maryna.
Sonia's calculations:
- For 6 problems: 120 minutes → \( \frac{120 \text{ min}}{6 \text{ problems}} = 20 \text{ min/problem} \)
- For 18 problems: 360 minutes → \( \frac{360 \text{ min}}{18 \text{ problems}} = 20 \text{ min/problem} \)
- For 25 problems: 500 minutes → \( \frac{500 \text{ min}}{25 \text{ problems}} = 20 \text{ min/problem} \)
- For 60 problems: 1200 minutes → \( \frac{1200 \text{ min}}{60 \text{ problems}} = 20 \text{ min/problem} \)
Sonia consistently spends 20 minutes per problem.
Maryna's calculations:
- For 8 problems: 200 minutes → \( \frac{200 \text{ min}}{8 \text{ problems}} = 25 \text{ min/problem} \)
- For 15 problems: 375 minutes → \( \frac{375 \text{ min}}{15 \text{ problems}} = 25 \text{ min/problem} \)
- For 20 problems: 500 minutes → \( \frac{500 \text{ min}}{20 \text{ problems}} = 25 \text{ min/problem} \)
- For 50 problems: 1250 minutes → \( \frac{1250 \text{ min}}{50 \text{ problems}} = 25 \text{ min/problem} \)
Maryna consistently spends 25 minutes per problem.
Comparison:
- Sonia: 20 min/problem
- Maryna: 25 min/problem
Therefore, Maryna spent more time writing per problem at the unit rate of 25 min/problem.
The correct response is: Maryna spent more time writing per problem at the unit rate of 25 min/problem.