From the Super Mario Wiki
Flutter Finish is a two-player minigame in Yoshi's New Island. It is a remake of Flutter Challenge from Yoshi's Island DS. The objective of the minigame is to flutter jump as far as possible in one minute. A Yoshi starts the minigame in a cloudy area with coins nearby. The player who gets the most points at the end is the winner.
The points are given as follows:
The two numbers are added together to determine the total score.