An online fax company, EFaxIt. com, has a customer plan where a subscriber pays a monthly subscription fee of $10.5 dollars and can send/receive 40 fax pages at no additional cost. For each page sent or received past the 40 page limit, the customer must pay an overage fee of $0.09 per page. The following expression gives the total cost, in dollars, to send p pages beyond the plan's monthly limit.
C=0.09p+10.5
If the monthly bill under this plan comes out to be $16.8, what was the total number of pages that were sent or received?