add task 1

src/task1 - Multiples of 3 and 5.hs

@@ -0,0 +1,15 @@
+import System.IO
+import Data.List
+
+isDivisibleBy3 :: Int -> Bool
+isDivisibleBy3 n = mod n 3 == 0
+
+isDivisibleBy5 :: Int -> Bool
+isDivisibleBy5 n = mod n 5 == 0
+
+isDivisibleBy3Or5 :: Int -> Bool
+isDivisibleBy3Or5 n = isDivisibleBy3 n || isDivisibleBy5 n
+
+main = do
+  let numbersDivisibleBy3Or5 = filter isDivisibleBy3Or5 [1..1000]
+  putStrLn $ show $ sum numbersDivisibleBy3Or5