Final answer:
To determine how many questions Darrow missed on the Institute entrance exam, we need additional information. If he answered 16 or more questions correctly, he did not miss any questions.
Step-by-step explanation:
The number of questions Darrow missed on the Institute entrance exam can be determined by subtracting the number of questions he answered correctly from the total number of questions on the exam. Based on the given solution 2.21, 70% of students answered 16 or fewer questions correctly and 30% of students answered 16 or more questions correctly.
Since Darrow is not specified in either group, we cannot determine the exact number of questions he missed without additional information. However, we do know that a higher percentile is considered good, so if Darrow answered 16 or more questions correctly, he did not miss any questions.