Regression to the mean

Hi, I'm a first-time poster struggling though my statistics class, and I was hoping someone could point me in the right direction for this particular homework question, which deals with the phenomenon "regression to the mean."

We're told that we have data that tells us the exam scored of all 346 students took a specific exam over a 10-year period. The least squares regression line for predicting final exam score from midterm exam score is y=46.6 + .41x. Octavio (what a name!) score 10 points above the class mean on the midterm, and we want to find out his predicted final exam score.

I know I need to find the predicted final score for the class mean midterm score, but I can't figure out how to do that! This is all the information I'm given.

I know that b (slope) is r(Sy/Sx), but I don't have any of these values to plug in to figure out the value of the mean midterm score.

If someone could help me out, I'd really appreciate it!