Question

In the Solutions to the Sample Questions for Exam 1, Question 10b) has a solution of -r/4. I don't see the logic to that answer. The logic is that the solution is A*-r, which is correct, but then they simplify by stating A=1/4, which is incorrect. A equals 1/4*Ao, which would make the correct answer -r/4*Ao. What am I missing?

Answer 1

You're right, it's a typo