1. The problem statement, all variables and given/known data I uploaded a picture to describe the problem. Oh yes, if anyone is wondering, the constant "c" = Var(R2) = 0.0046 . 2. Relevant equations 3. The attempt at a solution I uploaded my attempt at the solution. However, my method took me forever to get the answer, if I tried to do the calculations. If this was a testing environment, I am not sure if I will have enough time to answer the question. I do not know if there is any SIMPLE methods out there to answer this question! Can anyone please provide me with any tips or hints to do this problem the most efficient and clear-cut way? Thank you so much.