Answer
$t=15n+900$
Work Step by Step
Given the previous model:
Total cost = (Rate of closed seats)*(Number of closed seats) + (Rate of remaining seats)*(number of remaining seats
or:
$t = (45)*(n) + (30)*(30-n)$
We can first simplify the equation by multiplying the contents of the parentheses together:
$t=45n+900-30n$
Then simplify $45n$ and $-30n$ into $15n$ to eliminate like terms, to get the answer:
$t=15n+900$