At the Presidents Day sale, a customer can bring in a coupon for a 10%, 20% or 30% discount off of total purchases. When paying, a clerk will use a VB application to record the sale. Based on the coupon presented, the clerk will select one of the following Radio Buttons named: Discount10RadioButton, Discount20RadioButton, Discount30RadioButton.

This application also declares the following constants and variables: Const DISCOUNT_10Decimal as Decimal = 0.1D Const DISCOUNT_20Decimal as Decimal = 0.2D Const DISCOUNT_30Decimal as Decimal = 0.3D

Write syntactically correct Visual Basic.NET code to calculate the final purchase price after discount and save it in the Decimal variable PurchaseTotalDecimal. The total purchase amount was already calculated and it is stored in the Decimal variable named PurchaseGrossTotalDecimal. No taxes are being charged.