Percentages involving Finances: Discount and GST

Jimmy and Richard have lunch together at a restaurant. The receipt is as follows:

1. Complete the receipt by finding the following:
   1. the discount in percentage,
   2. the service charge amount,
   3. the GST amount (Round to the nearest cent),
   4. the total price of this meal.
2. Jimmy argues that it would be cheaper in total if the service charge and GST are included before discount. Do you agree with Jimmy? State your reasons by providing detailed workings.