Carl's credit company determines his minimum monthly payment by adding all new interest to 1% of the outstanding principal. The credit card company charges an interest rate of 0.039698% per day. On March 17, Carl uses his credit card to purchase airline tickets for his family for $2600. He makes no other purchases during march.
a. Assuming Carl had no new interest, determine Carl's minimum payment on April 1, his billing date.

b. On April 1, instead of making the minimum payment, Carl makes a payment of $500. Assuming there are no additional charges or cash advances, determine Carl's minimum payment due on May 1.