i have beef with this 2014 hsc question (1 Viewer)

[jane1820]

this is a 2014 math ext1 hsc question 8. multiple choice

apparently the answer is D BUT LIKE I DONT GET IT
the question says 'be CHOSEN' SO WHY ISNT IT 15C6???????????????
In this instance we are arranging ALL of the 15 and emphasising on the 6 but why since the question says 'be chosen and then arranged in a circle?' arent we meant to chose and arrange ONLY the 6

i started like this:
(15C6 x 5!)
didnt finish and then stopped thinking as soon as i saw the answers include 15 and 14 factorials

 

[quarkkkk]

15C6 = 15!/9!6!

 

[=)(=]

View attachment 47435

this is a 2014 math ext1 hsc question 8. multiple choice

apparently the answer is D BUT LIKE I DONT GET IT
the question says 'be CHOSEN' SO WHY ISNT IT 15C6???????????????
In this instance we are arranging ALL of the 15 and emphasising on the 6 but why since the question says 'be chosen and then arranged in a circle?' arent we meant to chose and arrange ONLY the 6

i started like this:
(15C6 x 5!)
didnt finish and then stopped thinking as soon as i saw the answers include 15 and 14 factorials

15C6 then there are 5! ways of arranging them in a circle

 

[jane1820]

15C6 = 15!/9!6!

The answer is D
15!/9!6

 

[cristal]

15c6 * 5! For table
If you expand 15C6 it becomes D

 

[jane1820]

Oh ok so i was right,
nvm i dont have beef anymore (this is why u dont do ext math at night)