The 9th term of an A.P. is 499 and the 499th term is 9. The term which is equal to zero is:
Answer: B
Given \(a+8d=499\) and \(a+498d=9\). Subtracting gives \(-490d = 490 \Rightarrow d=-1\). Substituting back, \(a+8(-1)=499 \Rightarrow a=507\). We want to find n for which \(a_n=0\). \(a_n = a+(n-1)d = 0 \Rightarrow 507 + (n-1)(-1) = 0 \Rightarrow 507 = n-1 \Rightarrow n=508\). The 508th term is zero.