The bill, please!

• Create three variables:
  • $price of a drink (= € 2.65)
  • $number of drinks (= 13)
  • Member $reduction (= 10%)
• Calculate the total amount the customer has to pay, based on the value of these variables
• Show the value of the variables and the total amount of the bill
• Change the value of the variables $price, $number and $reduction to generate some other bills