Shawn Bixby borrowed $37,000 on a 150-day, 10% note. After 70 days, Shawn paid $4,000 on the note. On day 101, Shawn paid an additional $6,000. Use ordinary interest. a. Determine the total interest use the U.S. Rule. (Do not round intermediate calculations. Round your answer to the nearest cent.) b. Determine the ending balance due use the U.S. Rule. (Do not round intermediate calculations. Round your answer to the nearest cent.)