The selling price of a pencil box was $4. Chee Keong bought the pencil box and paid $4.28 including GST. What percentage of milk was left?

always proof-read your question before posting

lol sorry :/

To determine the percentage of milk left in this scenario, we need some additional information. The question seems to be missing a crucial detail regarding milk. Could you please clarify the relation between the selling price of the pencil box and the percentage of milk left?