math
posted by Shan on .
in a survey of 260 dancers:
172 knew the ballroom dances
145 knew latin dances
102 knew swing dances
of these, 65 knew the ballroom and swing dances.
93 knew ballroom and latin dances
56 knew latin and swing dances
31 dancers indicated they knew all 3 styles of dance
1. how many knew only ballroom dances
2. how many knew only swing dances
3. how many knew exactly 2 of the 3 dances
4. how many knew latin and swing dances, but not ballroom dances
5. how many knew none of these dances

1. 172  65  93 = ?
2. same process, except with swing.
3. 65 + 93 + 56 = ?
4. 56
5. 260  172  56 = ?