Add all the A tasks

Task/Arithmetic-Rational/Scala/arithmetic-rational-2.scala

@@ -0,0 +1,15 @@
+def find_perfects():Unit=
+{
+   for (candidate <- 2 until 1<<19)
+   {
+      var sum= ~Rational(candidate)
+      for (factor <- 2 until (Math.sqrt(candidate)+1).toInt)
+      {
+         if (candidate%factor==0)
+            sum+= ~Rational(factor)+ ~Rational(candidate/factor)
+      }
+
+      if (sum.denominator==1 && sum.numerator==1)
+         printf("Perfect number %d sum is %s\n", candidate, sum)
+   }
+}