F3习题请教 following

mani_ho

The following balances relate to Putney:

                                                                  $

Receivables at 1.1.x8                                 34500

Cash received from credit customers           229900

Contra with payables                                  1200

Discounts allowed                                      17890

Cash sales                                                 24000

Irrecoverable debts                                    18600

Increase in allowance for receivables            12500

Discounts received                                     15670

Receivables at 31.12.x8                              45000

What is the revenue figure reported by Putney in the year ended 31 December 20x8?

A. $275870

B. $278090

C. $290590

D. $302090

 

这道习题的答案是D，解释是Credit Sales 278090+Cash sales 24000，得到D这个答案。但是我试了很多次，还是算不出278090这个数字，所以请老师详细解答一下。谢谢！

 

我是完全没会计基础的考生，真的十分后悔决定考ACCA，现在脑子里乱得很，被无数的数字和double entry搞得都快吐了，没办法，先去考一次，考不过就放弃算了。