Sequences & Series · JEE Main previous year questions

2006 2 questions

1. Q92006 · 29 Apr 2006 · Shift 1

   Let $a_1,a_2,a_3\dots$ be terms of an A.P. If $\frac{a_1+a_2+\cdots +a_p}{a_1+a_2+\cdots +a_q}=\frac{p^2}{q^2}$, $p\ne q$, then $\frac{a_6}{a_{21}}$ equals

   1. A.$\frac{41}{11}$
   2. B.$\frac{7}{2}$
   3. C.$\frac{2}{7}$
   4. D.$\frac{11}{41}$
   Show answer

   Answer: D

2. Q102006 · 29 Apr 2006 · Shift 1

   If $a_1,a_2,\dots a_n$ are in H.P., then the expression $a_1{a}_2+a_2{a}_3+\cdots +a_{n-1}{a}_n$ is equal to

   1. A.$n(a_1-a_n)$
   2. B.$(n-1)(a_1-a_n)$
   3. C.$n{a}_1{a}_n$
   4. D.$(n-1)a_1{a}_n$
   Show answer

   Answer: D