Final answer:
The shelter should expect to earn $5 for each ticket sold.
Step-by-step explanation:
To calculate how much the shelter should expect to earn for each ticket sold, we need to consider the number of tickets sold and the prizes won.
Out of the 990 tickets that do not win any prize, the shelter earns $5 for each ticket sold, so the total revenue from these tickets is 990 * $5 = $<<990*5=4950>>4950.
For the 13 tickets that win a free adoption valued at $20 each, the shelter does not earn any money from these tickets.
Finally, for the one ticket that wins $154 worth of pet supplies and toys, the shelter also does not earn any money from this ticket.
Therefore, the total revenue earned by the shelter for each ticket sold is $4950 / 990 = $<<4950/990=5>>5.