Assume the hospitality operation instead uses a periodic inventory system. Name the accounts affected by the following transactions and specify whether the effect is an increase or a decrease.

a. Liquor sales for the day total $525, $400 of which was paid in cash with the balance charged to guests' open accounts.

b. A storeroom purchase of liquor totaling $725 is charged by the operation to an open account.

c. A direct purchase of liquor totaling $67 is made. Check number 978 is issued upon purchase.