Answer:
The answer is: I believe the question was not copied correctly since the numbers don't match.
The recorded transactions should be:
- Dr Cash 420,000
- Cr Sales Revenue of 300,000
- Cr Unearned Service Revenue of 120,000
Cash account should be debited, since it's an asset. Sales revenue should be credited since it increases equity.Unearned revenue is a type of liability, so it should be credited.