If I was asked to give an example of the DR and CR entries for the following: Cash sale of $1100, Credit sale to B Brown for $990, Cash purchase of $880, credit purchase from G Green for $770, how would I set this out?

Analyze each transaction and determine the element of financial statements that fit the transaction and then make the necessary entry

Remember the following:
D - Debits
E - Expense acocunts
A - Assests
D - Dividends

C - Credits
U - Uneanred Revenues
R - Revenues
L - Liabilities
S - Shareholder's equity, Owners Equity

This will help to to know what the normal account balance should be; a Debit or Credit.

For Example an asset has a normal Debit Balance while a Liability has a Credit Balance.