Quiz Discussion

If the sum of three consecutive terms of an increasing A.P. is 51 and the product of the first and third of these terms is 273, then the third term is :

• 1] 13
• 2] 9
• 3] 21
• 4] 17

If log 2, log (2^x -1) and log (2^x + 3) are in A.P, then x is equal to ___

• 1]

   

  5/2

• 2]

  log₂5

• 3]

  log₃2

• 4]

   

  3/2

If 18th and 11th term of an A.P. are in the ratio 3 : 2, then its 21st and 5th terms are in the ratio

• 1] 3 : 2
• 2] 3 : 1
• 3] 1 : 3
• 4] 2 : 3

If the sum of p terms of an A.P. is q and the sum of q terms is p, then the sum of (p + q) terms will be

• 1] 0
• 2] p - q
• 3] p + q
• 4] -(p + q)

If k, 2k – 1 and 2k + 1 are three consecutive terms of an AP, the value of k is

• 1]

  -2

• 2]

  -3

• 3]

  2

• 4]

  3

The first and last term of an A.P. is a and l respectively. If S is the sum of all the terms of the A.P. and the common difference is given by \(\frac{{{l^2} - {a^2}}}{{k - \left( {l + a} \right)}}\)   then k = ?

• 1] S
• 2] 2S
• 3] 3S
• 4] None of these

Find the n^th term of the following sequence :
5 + 55 + 555 + . . . . T_n

• 1]

   

  5(10ⁿ - 1) 

• 2]

   

  5ⁿ(10ⁿ - 1)

• 3]

  5/9×(10ⁿ−1)

     

• 4]

  (5/9)ⁿ×(10ⁿ−1)

The 3rd and 6th term of an arithmetic progression are 13 and -5 respectively. What is the 11th term?

• 1] -29
• 2] -41
• 3] -47
• 4] -35

If Sn denote the sum of the first n terms of an A.P. If S2n = 3Sn , then S3n : Sn is equal to

• 1] 4
• 2] 6
• 3] 8
• 4] 10

If the sum of n terms of an A.P. be 3n2 + n and its common difference is 6, then its first term is

• 1] 2
• 2] 3
• 3] 1
• 4] 4