Answer:
cash 20,000,000 debit
unearned revenue 20,000,000 credit
Explanation:
Record the advance collection of $20 million for iTunes gift card.
When a gift card is sold, Apple Inc assume the obligation of latter provide iTunes in the near future or do cash reimbursement therefore; this isn't revenue. It is a liability. Apple will generate revenue when the gift ard are redeem not at sale.