Answer:
to entertain the reader with a story of two sisters training for and competing in a youth triathlon.
Step-by-step explanation:
For any piece of writing there is a purpose of the author. It may be of entertaining, teaching, criticizing, persuading or amusing the readers. The purpose of the writing the given extract of the author is to entertain the readers. The story is about the two sisters' training and competition in a youth triathlon. The two sisters participated in the race. It was the first time for the younger sister, Kayla. She has been coached and trained by her elder sister, Brooke, who has taken part in triathlon three times.