gistfile1.rb

require "bigdecimal"
montant = BigDecimal.new(ARGV[0])

GSTpercent = 5 
QSTpercent = BigDecimal.new("8.5")

myGST = montant * GSTpercent / 100 
myQST = (montant + myGST) * QSTpercent / 100 

total = montant + myGST + myQST

printf "Sous-total:\t%.2f\n", montant
printf "TPS (%.2f%%):\t%.2f\n", GSTpercent, myGST
printf "TVQ (%.2f%%):\t%.2f\n", QSTpercent, myQST
printf "Total:\t%.2f\n", total.round(2)