Quiz Discussion

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

For an A.P. if a25 - a20 = 45, then d equals to:

• 1] 9
• 2] -9
• 3] 18
• 4] 23

The common difference of the A.P. \(\frac{1}{3}, \frac{{1 - 3b}}{3} , \frac{{1 - 6b}}{3}\)   . . . . . . is

• 1]

  \(\frac{1}{3}\)

• 2]

  \( - \frac{1}{3}\)

• 3]

  -b

• 4]

  b

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

The sum of the first 16 terms of an AP whose first term and third term are 5 and 15 respectively is

• 1] 600
• 2] 765
• 3] 640
• 4] 680
• 5] 690

For A.P. T18 - T8 = ........ ?

• 1] d
• 2] 10d
• 3] 26d
• 4] 2d

If a, b, c are in A.P., then (a – c)²/ (b² – ac) =

• 1]

  3

• 2]

  4

• 3]

  1

• 4]

  2

Consider an infinite G.P. with first term a and common ratio r, its sum is 4 and the second term is 3/4, then

• 1]

  a = 7/4, r = 3/7

• 2]

  a = 2, r = 3/8

• 3]

  a = 3, r = 1/4

• 4]

  a = 3/2, r = ½

If 7 times the seventh term of an Arithmetic Progression (AP) is equal to 11 times its eleventh term, then the 18th term of the AP will be

• 1] 0
• 2] 1
• 3] 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