Question

In how many ways can 3person study groups beselected from a class of 25students?Note: nrn!r!(n-r)!nEnter

Answer 1

2,300

Step-by-step explanation:

This is given as:

`\begin{gathered} 25\text{ combination 3 represented as:} \\ ^nC_r=(n!)/(r!(n-r)!) \\ n=25 \\ r=3 \\ ^(25)C_3=(25!)/(3!(25-3)!) \\ ^(25)C_3=(25*24*23*22!)/(3!*22!) \\ ^(25)C_3=(25*24*23)/(3*2*1) \\ ^(25)C_3=2300 \end{gathered}`

Therefore, there are 2,300 ways that 3 persons can be selected from 25 people