Ques. 1JEE Main 2024, 29 January (Morning Shift)
If 11C12+ 11C23+ + 11C910= nm with (n,m)=1, then n+m is equal to .
Answer
2041
Solution
∵ 11Crr+1= 112 12Cr+1
Sum = 112 (12C2+12C3+ +12C10 )
= 112 (212-12C0-12C1-12C11-12C12 )
= 4096-2612= 20356
⇒ n = 2035, m = 6 ⇒ n + m = 2041
Answer: 2041