Praxis Core Academic Skills for Educators: Mathematics (5733)Statistics and ProbabilityMedium
A student is planning a schedule for their final exams. There are 4 different exams to be taken over 4 consecutive days, with only one exam per day. In how many different orders can the student schedule their exams?
- A24
- B12
- C4
- D120
Show answer & explanationAnswer & explanation
Correct answer: A. 24
This is a permutation problem because the order of the exams matters. For 4 exams to be scheduled in 4 days, the number of different orders is 4! (4 factorial). 4! = 4 * 3 * 2 * 1 = 24.
Why the other options are wrong
- B. This would be 3! * 2, or an incorrect calculation.
- C. This is simply the number of exams, not the number of arrangements.
- D. This would be 5!, which is for 5 items.
Permutations (n items)
The number of distinct ways to arrange a set of 'n' unique items in a specific order.
- Order of arrangement matters.
- Calculated using factorial notation (n!).
- Used when all items are selected and arranged.
Memory trick: Permutation: Position matters; Combination: Committee, order doesn't.