Step-by-step explanation:
1. Since 39 is 3/5 of the club, divide by 3 to get 1/5 of the club
2. 1/5 of the club is 13 people
3. Multiply 13 by 5 to get 5/5 of the club (which is the whole club)
4. The whole club is 65 people
5. You can check it because 65×3/5=39
