TASK DEFINITION: In this task, you need to reverse all words of a given length in the sentence. The number of letters in a word determine its length. For example, the length of the word "apple" is 5.
PROBLEM: Sentence: 'a couple of elephants that are in some water'. Reverse all words of length '6' in the given sentence.

SOLUTION: a elpuoc of elephants that are in some water

PROBLEM: Sentence: 'a man on a motor bike pulling a person on a skate board'. Reverse all words of length '5' in the given sentence.

SOLUTION: a man on a rotom bike pulling a person on a etaks draob

PROBLEM: Sentence: 'a boat is traveling down a narrow waterway'. Reverse all words of length '6' in the given sentence.

SOLUTION:
a boat is traveling down a worran waterway