2. An electronic notice board, measuring 3m x 2m, is mounted on a square wall
with sides 6m x 6m. Pablo must paint all of the wall not covered by the notice
board.
A litre of paint covers 2.80m2 of wall. Paint can be bought in 1 litre cans costing
$10 each or 2.5 litre cans costing $20 each.
What is the least that Pablo can spend on paint that allows him to complete his
painting job?