Adds @RobFreiburger's solutions.

1/RobFreiburger.rb

@@ -0,0 +1,9 @@
+sum = 0
+
+1.upto(999).each do |i|
+	if (i % 3 == 0) || (i % 5 == 0)
+		sum += i
+	end
+end
+
+puts sum

2/RobFreiburger.rb

@@ -0,0 +1,18 @@
+sum = 0
+
+def fib(n)
+	return n if n < 2
+	vals = [0, 1]
+	(n-1).times do
+		vals.push(vals[-1] + vals[-2])
+	end
+	return vals
+end
+
+fib(34).each do |value|
+	if value <= 4000000
+		sum += value if value.even?
+	end
+end
+
+puts sum

3/RobFreiburger.rb

@@ -0,0 +1,2 @@
+require 'prime'
+puts Prime.prime_division(600851475143).last[0]

4/RobFreiburger.rb

@@ -0,0 +1,13 @@
+largest_palindrome = 0
+
+(100..999).each do |x_value|
+	(100..999).each do |y_value|
+		test_value = x_value * y_value
+
+		if (test_value.to_s == test_value.to_s.reverse) && (test_value > largest_palindrome)
+			largest_palindrome = test_value
+		end
+	end
+end
+
+puts largest_palindrome

5/RobFreiburger.rb

@@ -0,0 +1,16 @@
+# Is computationally-inefficient
+
+smallest_num = 1
+
+while true do
+	results = Array.new(20)
+	(1..20).each do |i|
+		results.push((smallest_num % i) == 0)
+	end
+
+	break unless results.include?(false)
+
+	smallest_num += 1
+end
+
+puts smallest_num