Question

I need help ASAP please

Answer 1

Answer:

The correct option is D. The total number ways to select 3 student from 10 stents is 120.

Step-by-step explanation:

The total number of students is 10.

The number of selected students is 3.

According to the combination formula.

$^nC_r=\frac{n!}{r!(n-r)!}$

Where, n is total possible values and r is number of selected values.

$^{10}C_3=\frac{10!}{3!(10-3)!}$

$^{10}C_3=\frac{10\times 9\times 8\times 7!}{3\times 2!\times 7!}$

$^{10}C_3=120$

Therefore option D is correct.

Answer 2

Answer:

Choice D is correct answer.

Step-by-step explanation:

We have to find number of ways to choose students to go to library.

From question statement , we observe that

Numbers of students = n= 10

Number of selected students = r = 3

Order doesn't matter.

Hence,we use the formula of combination to solve this question.

$^{n} C_{r} = n!/(n-r)!.r!$

putting the values of n and r in abobe formula ,we get

$^{10} C_{3} = 10!/ (10-3)!.3!$

$^{10}C_{3} =10!/7!.3!$

$^{10} C_{3}$= 120 ways

Hence, there are 120 ways to choose the students to go to library.