Answer:
c.
Step-by-step explanation:
Let x be the number of adults in Tim's family. Then (17 - x) is the number of children in Tim's family.
We have $34x + $31.5(17 - x) = $558.
$34x + $31.5(17 - x) = $558
$34x + $535.5 - $31.5x = $558
$2.5x = $22.5
x = 9
Hence the answer is c.