Answer:
[tex]Probability = \frac{1}{792}[/tex]
Step-by-step explanation:
Given
[tex]Questions = 12[/tex]
[tex]Selection = 5[/tex]
Required
Probability of grading the selected 5 by Andrew
First, we need to determine the total number of selections.
This is calculated as: [tex]^{12}C_{5}[/tex]
Solving further:
[tex]^{12}C_{5} = \frac{12!}{(12-5)!5!}[/tex]
[tex]^{12}C_{5} = \frac{12!}{7!5!}[/tex]
[tex]^{12}C_{5} = \frac{12*11*10*9*8*7!}{7!*5*4*3*2*1}[/tex]
[tex]^{12}C_{5} = \frac{12*11*10*9*8}{5*4*3*2*1}[/tex]
[tex]^{12}C_{5} = \frac{95040}{120}[/tex]
[tex]^{12}C_{5} =792[/tex]
There is only 1 for Andrew's question selection.
So, the required probability is:
[tex]Probability = \frac{1}{792}[/tex]
