HF Magazines Corp. sells three-year magazine subscriptions for $180 cash each. The cost of producing and delivering each magazine is $2 paid in cash at the time of delivery. HF’s sales activity for the year follows: 

■ On January 1, 2020, HF sells 10,000 subscriptions. 

■ On April 1, 2020, HF sells 5,000 subscriptions. 

■ On November 1, 2020, HF sells 12,000 subscriptions. 

HF delivers the magazines at the end of the month. HF’s year-end is December 31. 

Required: 

a. Prepare journal entries to record the subscription sales during the year. 

b. Prepare summary journal entries to record the revenue earned during the year and the related expense.