I don't get how to solve question 19 for this question

Copper Corporation has the following sales budget for the last six months of 2007: July $200,000 October $180,000 August 160,000 November 200,000 September 220,000 December 188,000 Historically, the cash collection of sales has been as follows: 65 percent of sales collected in month of sale, 25 percent of sales collected in month following sale, 8 percent of sales collected in second month following sale, and 2 percent of sales is uncollectible. 18) Cash collections for September are 18) A) $161,400 B) $143,000 C) $199,000 D) $240,000 E) $204,000 19) What is the ending balance of accounts receivable for September assuming uncollectible balance is 19) written off after the second month? A) $89,800 B) $88,000 C) $97,000 D) $199,000 E) $93,000