You can set this up as .20 x 62 which will give you $12.4 or $12.40. You get .20 by converting 20% to a decimal. Also you can simply put 60-20% on a calculator.
You have a disount of 10% so you'll be paying only 90% of the actual price so your ticket will be Adding the service charge to the total, you'll have to pay 110.5% of the total so what you're paying is