Ann established a home equity line of credit. The interest rate is recalculated at the beginning of each year at prime + 1% convertible monthly. Ann withdrew $2,000 on 1/1/90 and began making payments of $100 every month starting on 2/1/90. The prime rate increased from 11% on 1/1/90 to 12% on 1/1/91. Immediately after making her payment on 4/1/91, Ann withdrew an additional $4,000. Her payments remained at $100 per month. 

What was the amount of principal, P, in her next payment on 5/1/91?