Answer:
B.120
Explanation:
The questions says in how many ways band she choose 3 of the 10 students
Using Combination Formula, which says
C = n! / (n! (n - r) !)
n represents the total number of students
r represents the students he want to choose
The number of combinations 3 out of 10
¹⁰₃C = 10! / (3! (10 - 3) !)
= 10! / 3! 7!
= 10*9*8*/ 3*2*1/ 7*6*5
= 3628800 / 6*5040
= 3628800 / 30240
= 120ways