Given:
When there are 24 atendees, the cost = $312
Let's find cost when there are 54 atendees.
Apply the proportionality equation:
24 atendees = $312
54 atendees = $x
Hence, we have the equation:
Cross multily and solve for x.
We have:
Divide both sides of the equation by 24:
Therefore, when there are 54 atendees, Adele's graduation picnic cost will be $702.
ANSWER:
$702