Answer and Explanation:
The journal entries are shown below:
a)
i) Accounts receivable $15,000
To Service revenue $15,000
(Being the service revenue on account is recorded)
ii) Cash $10,000
To Accounts receivable $10,000
(Being cash received is recorded)
b)
i) Cash $2,000
To Unearned Service revenue $2,000
(being cash received is recorded)
ii) Unearned Service revenue $1,500
To Service revenue $1,500
(being unearned service revenue is recorded)