A set consist of 2k-1 element. What is the number of subsets of this set which contain at most k-1 elements?	Select.
A) 2^(2k-2)
B) 2^(2k) - 2
C) 2^(2k) -1
D) 2^(2k)
E) 2^(2k-1)
I used k=3, so then we have   5!/2!3! + 5!/4!1! + 5!/0!5!    10 + 5 + 1= 
<gadget id="calculator"> 10 + 5 + 1</gadget>
<output>16</output>
16   So our target is 16   Now replace in answer choices   2^(2k-2) gives us 2^4= 16   Hence 2^(2k-2) is the correct option   Read carefully it says at most so keep in mind that picking a small number such as 3 will help you save time since you have to list fewer outcomes   2^(2k-2)void 2 since you will get 1 arrangement (k-1) and may be risky since 1 is a number with certain unique properties
<result>A</result>
A set consist of 2k-1 element. What is the number of subsets of this set which contain at most k-1 elements?