ocr accounting level 2 - journal entries and produce a rvised trial balance?

Question

i have got 2 invoices one sales invoice has been entered correctly in accounts but on the wrong side , invoice 2 is credit note that has been entered twice in the accounts,can anybody explain how i correct these errors

Answer 1

Your question is not very clear but I'll try my best.

One sales invoice has been entered on the wrong side - I presume you reversed the debit and credit. Assume it's for $100. What you did wrongly was:
Dr Sales 100
Cr A/cs receivable 100

To correct that, you just reverse the above entry, but double the amounts,
Dr A/cs receivable 200
Cr Sales 200

The net effect of the above entries is:
Dr A/cs receivable 100
Cr Sales 100

which is what you should have done in the 1st place.

Your 2nd qn is confusing. An invoice is an invoice and a credit note is a credit note. A credit note is what you give your customer if he returns damaged goods (or for other reasons) How can invoice 2 be a credit note? Anyway, you have a credit note that has been entered once:
Dr Sales returns 100
Cr A/cs receivable 100

and one more time (wrongly),
Dr Sales returns 100
Cr A/cs receivable 100

So to correct the double posting just reverse the entry once:
Dr A/cs receivable 100
Cr Sales returns 100

Just remember: sales is a credit, so a sales return must be a debit.