test.rb

inputProducts = gets
total = 0
products = {
            "A" => { "1" => 2.00, "4" => 7.00 },
            "B" => { "1" => 12.00 },
            "C" => { "1" => 1.25, "6" => 6.00 },
            "D" => { "1" => 0.15 }
        }
inputArray = inputProducts.split('')    # input products
counts = Hash.new                       # number of item
products.each_key do |key|
    counts[key] = inputArray.count(key)
end
total = 0.0
counts.each_key do |key|
    if products[key].count > 1
        groupKey = products[key].keys[1]
        groupUnit = counts[key] / groupKey.to_i
        singleCount = counts[key] % groupKey.to_i
        subtotal = groupUnit * products[key][groupKey] + singleCount * products[key]['1']
        total += subtotal
    else
        subtotal = counts[key] * products[key]['1']
        total += subtotal

    end    
    puts "Subtotal: #{subtotal}"
end
puts "Final Total: #{total}"