On a ski slope there are 9 tracks.if each person went down once,how many skiers and snow boarders were there?
https://academicpapers.net/wp-content/uploads/2020/08/LOGO-300x75.png00Lizhttps://academicpapers.net/wp-content/uploads/2020/08/LOGO-300x75.pngLiz2021-07-25 06:15:542021-07-25 06:15:54On a ski slope there are 9 tracks.if each person went down once,how many skiers and snow boarders were there?