diff --git a/exercises/Set1.hs b/exercises/Set1.hs
index 00a9c80..81d2fb4 100644
--- a/exercises/Set1.hs
+++ b/exercises/Set1.hs
@@ -47,6 +47,10 @@ quadruple x = todo
 --
 -- PS. if you can't remember how the distance is computed, the formula is:
 --   square root of ((x distance) squared + (y distance) squared)
+--
+-- Examples:
+--   distance 0 0 1 1  ==>  1.4142135...
+--   distance 1 1 4 5  ==>  5.0
 
 distance = todo
 
diff --git a/exercises/Set1Test.hs b/exercises/Set1Test.hs
index 30c09e1..9370bfd 100644
--- a/exercises/Set1Test.hs
+++ b/exercises/Set1Test.hs
@@ -55,7 +55,7 @@ ex4_distance = do
   y1 <- elements [-5..5]
   let x2 = x1+deltax
   let y2 = y1+deltay
-  return $ $(testing [|distance x1 x2 y1 y2|]) (dist=~?)
+  return $ $(testing [|distance x1 y1 x2 y2|]) (dist=~?)
 
 ex5_eeny_even = forAll_ $ \x -> $(testing [|eeny (2*x)|]) (?=="eeny")
 ex5_meeny_odd = forAll_ $ \x -> $(testing [|eeny (2*x+1)|]) (?=="meeny")