Question

There are 15 students in a social studies class. Two students will be selected to present their term projects today. In how many different orders can two students be selected?

Answer 1

To calculate the different orders in which two students can be selected, we use the permutation formula, which is:

nPr = n! / (n - r)!

where n is the total number of students (15 in this case) and r is the number of students we want to select (2 in this case).

Plugging in the values:

15P2 = 15! / (15 - 2)!
= 15! / 13!
= (15 x 14 x 13!) / 13!
= 15 x 14
= 210

Therefore, there are 210 different orders in which two students can be selected from a class of 15 students.