Answer: 7.
- A 7
- B 3
- C 6
- D 4
Correct answer: A. 7
Explanation: 10C3 = 10C(10-3) = 10C7. So 10C3 = 10C7.
Counting tree for selecting 2 items from {A, B, C} without repetition: 3 x 2 = 6 ordered arrangements.
Concept context
Counting, arrangements, and selections