Fix smallest reference

Author: Justin Ryan

src/main/java/learnrxjava/ObservableExercises.java

@@ -72,7 +72,7 @@ public Observable<Integer> exerciseReduce(Observable<Integer> nums) {
     }
 
     /**
-     * Retrieve the id, title, and smallest box art url for every video.
+     * Retrieve the id, title, and <b>smallest</b> box art url for every video.
      * 
      * Now let's try combining reduce() with our other functions to build more complex queries.
      * 

src/main/java/learnrxjava/ObservableSolutions.java

@@ -98,7 +98,7 @@ public Observable<JSON> exerciseMovie(Observable<Movies> movies) {
                 return v.boxarts.reduce((max, box) -> {
                     int maxSize = max.height * max.width;
                     int boxSize = box.height * box.width;
-                    if (boxSize > maxSize) {
+                    if (boxSize < maxSize) {
                         return box;
                     } else {
                         return max;