Quiz Discussion

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

The two geometric means between the number 1 and 64 are

• 1]

  8 and 16

• 2]

  2 and 16

• 3]

  4 and 8

• 4]

  4 and 16

The sum of first five multiples of 3 is:

• 1] 45
• 2] 65
• 3] 75
• 4] 90

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

The 2nd and 8th term of an arithmetic progression are 17 and -1 respectively. What is the 14th term?

• 1] -22
• 2] -25
• 3] -19
• 4] -28

What is the sum of the first 11 terms of an arithmetic progression if the 3rd term is -1 and the 8th term is 19?

• 1] 204
• 2] 121
• 3] 225
• 4] 104

How many 2-digit positive integers are divisible by 4 or 9?

• 1]

  32

• 2]

  22

• 3]

  34

• 4]

  30

Sum of n terms of the series \(\sqrt 2   +   \sqrt 8   +   \sqrt {18}   +   \sqrt {32}   +  \) ....... is

• 1]

  \(\frac{{n\left( {n + 1} \right)}}{2}\)

• 2]

  \(2n\left( {n + 1} \right)\)

• 3]

  \(\frac{{n\left( {n + 1} \right)}}{{\sqrt 2 }}\)

• 4]

  1

If an A.P. has a = 1, tn = 20 and sn = 399, then value of n is :

• 1] 20
• 2] 32
• 3] 38
• 4] 40

The number of terms of the A.P. 3, 7, 11, 15, ....... to be taken so that the sum is 406 is

• 1]

  5

• 2]

  10

• 3]

  12

• 4]

  14