13. On February 3, a company borrowed $50 000 on a demand loan from a bank. Interest on the loan is charged to the company's current account on the 11th of each month. The company repaid the loan with the following payments: with February 20 March 20 April 20 May 20 $10000 $10 000 $15 000 $15 000 $50 000 The rate of interest on the loan was originally 6%. The rate was changed to 7% on April 1, and to 6.5% on May 1. Calculate the interest payments required and the total interest paid