For number 12 you need to make an expression using the information given. a) 25g + 18r + 15b could be the expression.
b) The variables would be 25g for the 25 gold seats, 18r for the 18 red seats and 15b for the 15 blue seats.
c) Plug in the number given according to the variables.
25(100) + 18(250) + 15(200)
2500 + 4500 + 3000
7000 + 3000
$10,000