Question
Question: The sum of last eight coefficient in expansion (1 + x)<sup>15</sup> is...
The sum of last eight coefficient in expansion (1 + x)15 is
A
216
B
215
C
214
D
None
Answer
214
Explanation
Solution
S = 15C15 + 15C14 ….+ 15C9 + 15C8
\ S = 15C0 + 15C1 ……+15C6 + 15C7 2S = 215
Ž S = 214