Question on receivables budget

Youri Plc has the following opening and closing balances on its trade receivables budget for next year 2017. Opening balance on trade receivables (invoiced on 31 Dec 2006) - £56,000 Closing balance on trade receivables (invoiced on 30 Dec 2007) - £72,000 In 2007, credit sales are expected to be £276,000. The company offers a 10% discount on all amounts paid within one month of the invoice date. In 2007 the company expects 50%of eligible trade customers to take advantage of this discount. How much cash does Youri Plc expect to receive from customers during the year? The answer is £243,400 but I can’t understand how to find the amounts for November and December. Thank you.