Answer:
Journal to be posted on August 1, 2017
Debit Cash account             $157,080
Credit Deferred revenue     $157,080
Being entries to record cash received on August 1, 2017 for subscription to be sold.
Debit Deferred revenue    $65,450
Credit  Revenue (p/l)          $65,450
Being entries to recognized revenue earned from subscription as at December 31, 2017
Explanation:
Number of subscription sold = 9240
Selling price of each = $17
Amount received = 17 × 9240
                              = $157,080
Journal to be posted on August 1, 2017
Debit Cash account             $157,080
Credit Deferred revenue     $157,080
Being entries to record cash received for subscription to be sold 
On December 31 2017, the fee for 5 months would have been earned
= (5/12) × $157,080
= $65,450
Entries to be posted
Debit Deferred revenue    $65,450
Credit  Revenue (p/l)          $65,450
Being entries to recognized revenue earned from subscription as at December 31, 2017.