diff --git a/solutions/12_options/options1.rs b/solutions/12_options/options1.rs
index 1ffbb045..230af3af 100644
--- a/solutions/12_options/options1.rs
+++ b/solutions/12_options/options1.rs
@@ -4,8 +4,8 @@
 // `hour_of_day` is higher than 23.
 fn maybe_icecream(hour_of_day: u16) -> Option<u16> {
     match hour_of_day {
-        0..22 => Some(5),
-        22..24 => Some(0),
+        0..=21 => Some(5),
+        22..=23 => Some(0),
         _ => None,
     }
 }