Question 1173392
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In a school, every grade 10 student need to study 7 subjects out of 14. 
It is given that 4 of them are core subject, and the rest are optional. 
How many arrangements of the subjects are available for the students?
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        Based on the context, my common sense says me that this problem is about combinations,

        and not about permutations, as @CPhill calculates and treats it.


        So, I solve it differently, and my answer is different from that by @CPhill.



<pre>
Every student must take 4 core subjects, and a student should take 3 additional subjects, selecting them

from  14-4 = 10 remaining optional subjects.


So, the total number of all possible combinations is  {{{C[10]^3}}} = {{{(10*9*8)/(1*2*3)}}} = 120.     <U>ANSWER</U>
</pre>

Solved. The order of subjects in arrangements does not matter.


I am 137% sure that the treatment by @CPhill is not that the problem does require.