一道财务会计的英文问题..

问题描述:

一道财务会计的英文问题..
You are given the following information:
Receivables at 1 Jan 20X3 $10,000
Receivables at 31 Dec 20X3 $9,000
Total receipts during 20X3 (including cash sales of $5,000) $85,000
What are sales on credit during 20X3?
为什么答案是 79,000 难道一月的不算在20X3年吗

应收账款年初10000,年末9000. 中间收回货款85000,其中5000是现金售出,也就是应收账款收回80000,问非现金的售出,也就是期间应收账款增加额x
10000+x-80000=9000
x=79000