To find out how many quizzes Riley will have taken after attending 10 weeks of school, we can first determine the rate of quizzes per week based on the information given.
Riley took a total of 12 quizzes over the course of 3 weeks.
To find the number of quizzes per week (unit rate), we can divide the total number of quizzes by the number of weeks:
\[ \text{Quizzes per week} = \frac{12 \text{ quizzes}}{3 \text{ weeks}} = 4 \text{ quizzes/week} \]
Next, we calculate the total number of quizzes Riley will have taken after attending 10 weeks. We multiply the quizzes per week by the number of weeks attended:
\[ \text{Total quizzes} = 4 \text{ quizzes/week} \times 10 \text{ weeks} = 40 \text{ quizzes} \]
Therefore, after attending 10 weeks of school, Riley will have taken a total of 40 quizzes.