An investor has the option to allocate funds towards investing in stocks, bonds, or real estate. The expected returns for each investment are as follows: stocks offer an average annual return of $10\%,$ bonds offer an average annual return of $5\%,$ and real estate offers an average annual return of $8\%.$ If the investor decides to allocate an additional $$50,000$ towards stocks, what is the opportunity cost in terms of both bonds and real estate over a period of $5$ years?