Adding a explain compunding script.

explain-compounding.rb

@@ -0,0 +1,29 @@
+#!/usr/bin/env ruby
+
+initial_amount = 100000
+rate = 7
+years = 10
+
+puts "Use defaults - Amount: #{initial_amount}, Rate: #{rate}, Years: #{years}?"
+default = gets
+
+if default.include? "n"
+  puts "Enter amount: "
+  initial_amount = gets.to_i
+
+  puts "Enter rate of interest: "
+  rate = gets.to_i
+
+  puts "Enter total years: "
+  years = gets.to_i
+end
+
+amount = initial_amount
+
+puts "You invested #{amount}"
+years.times do |i|
+  amount = amount * ( 1 + (rate / 100.0) )
+  puts "At end of #{i+1} year: #{amount}"
+end
+
+puts "If you invest it for another #{years} years: #{amount * (( 1 + (rate / 100.0) ) ** years)}"