diff --git a/transform.Rmd b/transform.Rmd
index ed0edd9..03a0a45 100644
--- a/transform.Rmd
+++ b/transform.Rmd
@@ -325,7 +325,7 @@ flights_sml <- select(flights,
   air_time
 )
 mutate(flights_sml,
-  gain = arr_delay - dep_delay,
+  gain = dep_delay - arr_delay,
   speed = distance / air_time * 60
 )
 ```
@@ -334,7 +334,7 @@ Note that you can refer to columns that you've just created:
 
 ```{r}
 mutate(flights_sml,
-  gain = arr_delay - dep_delay,
+  gain = dep_delay - arr_delay,
   hours = air_time / 60,
   gain_per_hour = gain / hours
 )
@@ -344,7 +344,7 @@ If you only want to keep the new variables, use `transmute()`:
 
 ```{r}
 transmute(flights,
-  gain = arr_delay - dep_delay,
+  gain = dep_delay - arr_delay,
   hours = air_time / 60,
   gain_per_hour = gain / hours
 )