I am not sure how to start this problem...

"You have $13112 to invest in a stock portfolio. Your choices are Stock X with an expected return of 13.88 percent and Stock Y with an expected return of 10.38 percent. Of your goal is to create a portfolio with an expected return of 11.5 percent, how much money (in $) will you invest in Stock X? Answer to two decimals, carry intermediate calcs. to four decimals."