2.6. Combination Problems http://www.ck12.org
6.
2 8 MATH I I I (PRB) 3 (nCr) 4 ENTER
7.
1 9 MATH I I I (PRB) 3 (nCr) 6 ENTER
8.
3 3 MATH I I I (PRB) 3 (nCr) 2 ENTER
9.
2 7 MATH I I I (PRB) 3 (nCr) 8 ENTER
10.
2 0 MATH I I I (PRB) 3 (nCr) 4 ENTER
11.
3 8 MATH I I I (PRB) 3 (nCr) 9 ENTER