To obtain the necessary funds for an expansion, a small company took out three loans totaling $20,000. The company was able to take out a loan at 17%, took out another loan at 19%, and took out a third loan for the remainder at 18%. The second loan, at 19%, was $3,000 more than half of the first loan, at 17%. The annual interest was $3,620. How much did he borrow at 19%?