Quiz Discussion

How many terms are there in the GP 5, 20, 80, 320........... 20480?

• 1] 5
• 2] 6
• 3] 8
• 4] 9
• 5] 7

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 first term of an Arithmetic Progression is 22 and the last term is -11. If the sum is 66, the number of terms in the sequence are:

• 1]

  9

• 2]

  10

• 3]

  11

• 4]

  12

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

Which term of the A.P. 24, 21, 18, ............ is the first negative term?

• 1] 8th
• 2] 9th
• 3] 10th
• 4] 12th

In an A.P., if d = -4, n = 7, an = 4, then a is

• 1] 6
• 2] 7
• 3] 20
• 4] 28

If the nth term of an A.P. is 2n + 1, then the sum of first n terms of the A.P. is

• 1] n(n - 2)
• 2] n(n + 2)
• 3] n(n + 1)
• 4] n(n - 1)

Two A.P.’s have the same common difference. The first term of one of these is 8 and that of the other is 3. The difference between their 30th terms is

• 1] 11
• 2] 3
• 3] 8
• 4] 5

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

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