International City Trust (ICT) invests in short-term corporate bonds and construction loans. To encourage a diversified portfolio, the Board of Directors has placed limits on the amount which can be invested in any one type of investment. ICT has $500,000 to invest. The Board has recommended that at least 20 percent but no more than 30 percent should be invested in construction loans and that investment in short-term corporate bonds be twice as much as construction loans. The returns on the investment are 11 percent for corporate bonds and 15 percent for construction loans. Formulate as a linear programming problem.