In how many ways can a school president, a vice-president, and secretary be chosen from 21 students?

I'm not sure to find this answer since there is no order in which they are chosen.

the order does not matter. There are 21P3 ways to select an ordered group of 3 items from 21.

Whoever is chosen first, there are 21 available people.

20 for the 2nd, and 19 for the 3rd.

To find the number of ways to choose a school president, vice-president, and secretary from 21 students without considering the order, you can use the concept of combinations.

The number of ways to choose a president from 21 students is 21, as any of the 21 students can be selected.

For the remaining positions, the number of choices decreases by one each time. So, after the president is chosen, there are 20 students left to choose from for the vice-president position.

Similarly, after both the president and vice-president are chosen, there are 19 students remaining for the secretary position.

To obtain the total number of ways, you can multiply the number of choices at each step. Therefore, the total number of ways to choose a school president, vice-president, and secretary can be calculated as follows:

21 * 20 * 19 = 7980

Hence, there are 7980 ways to choose a school president, vice-president, and secretary from 21 students.