We assume all money is spent on new lighting. Since they currently have $160 and need $400 we can subtract what they currently have from what they need.
$400-$160 = $240
Since we know the price of the ticket and now know they need $240 we can divide our $240 with the price of each ticket ($3)
$240/$3 = 80
So the drama club has to sell 80 more tickets in order to afford new lighting
You can eliminate 81 because we know 
The dot is on approximately 9.32 (my estimate) so I would square that number:
(9.32)² = 86.8624 so if you round this you get 87
The solution for this problem is:
If there is 60 platters of B at a cost of $720:
(220 - 60 x 3) / 4 = 10 platters of A to make up for the deficit in hamburgers
(270 - 60 x 4) / 3 = 10 platters of A to make up for the deficit in hot dogs
(250 - 60 x 5) / 2 = 0 platters of A since there is no deficit in pigs feet
So 10 platters A are required at a cost of $150. $720 + $150 = for a total minimum cost of $870.
I wish I knew but same profile pic pog