net of cash discounts

Foster Industries sells on terms of 2/10, net 35. Gross sales last year were $450,000, and accounts receivable averaged $60,000. Half of Foster’s customers paid on Day 10 and took discounts. (a) What are Foster’s sales net of cash discounts taken? (b) What is the total dollar finance charge paid by the non-discount-paying customers? (c) What is the average collection period (DSO) for the nondiscount customers?