- Let $p$ be the proposition “I will practice more in Discrete Structure Course” and $q$ be the proposition “I will get an A+ in this course”. Express each of these as a combination of $p$ and $q$.
To get an A+ in this course, it is necessary for me to practice more in Discrete Structure Course.
My answer is $q\to p$ as $p$ is necessary for $q$. my instructor says it's wrong, what's the correct answer?
You are correct, and your professor is incorrect. Yes, when $p$ is necessary for $q$, it becomes $q \rightarrow p$.
Looking at this problem more informally: it may be necessary to practice more in order to get an A+, but of course that does not mean that everyone who practices more will get an A+ .. they also need to remain alive for the remainder of the course, for one thing ...