Nova Publications publishes a sport magazine. The magazine sells for $5 a copy on a newsstand. Yearly subscriptions to the magazine cost $50 per year (12 issues). During December 2018, Nova Publications sells 12,000 copies of the sport magazine at newsstands and receive payment for 30,000 subscriptions for 2019. Financial statements are prepared monthly.

a. Prepare the December 2018 journal entries to record the newsstand sales and subscriptions received.

b. Prepare the necessary adjusting entry on January 31,2019. The issue has been mailed to subscribers.