Quiz Discussion

If 18, a, b - 3 are in A.P. then a + b =

• 1] 19
• 2] 7
• 3] 11
• 4] 15

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

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 n terms of an A.P. is 3n2 + 5n, then 164 is its

• 1] 24th term
• 2] 27th term
• 3] 26th term
• 4] 25th term

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

• 1]

  6

• 2]

  7

• 3]

  20

• 4]

  28

How many terms are there in 20, 25, 30 . . . . . . 140?

• 1] 22
• 2] 25
• 3] 23
• 4] 24

Let S denotes the sum of n terms of an A.P. whose first term is a. If the common difference d is given by d = S_n – k S_n-1 + S_n-2 then k =

• 1]

  1

• 2]

  2

• 3]

  3

• 4]

  4

The sum of the first four terms of an A.P. is 56. The sum of the last four terms is 112. If its first term is 11, the number of terms is

• 1]

  10

• 2]

  11

• 3]

  12

• 4]

  13

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

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