Final answer:
The expression for the total cost of the tickets is (2 x $17) + (1 x $13), which simplifies to $47. The total cost of the tickets for William's family is $47.
Step-by-step explanation:
The expression for the total cost of the tickets for William's family can be calculated by multiplying the number of adult tickets ($17) by the number of adults in William's family, and multiplying the number of children tickets ($13) by the number of children in William's family.
The total cost can be found by adding the two results.
Let's assume William's family consists of 2 adults and 1 child.
We can substitute the values into the expression.
The expression would be (2 x $17) + (1 x $13).
Simplifying the expression gives us $<<2*17+1*13=47>>47.
Therefore, the total cost of the tickets for William's family would be $47.