Response to the following problem:
Fungus Audio Works Inc. warrants its products for one year. The estimated product warranty is 3% of sales. Assume that sales were $680,000 for January. In February, a customer received warranty repairs requiring $4,200 of parts.
a. Determine the warranty liability at January 31, the end of the first month of the current year.
b. What accounts are decreased for the warranty work provided in February?