Quiz Discussion

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. \(\frac{1}{{2b}} \frac{{1 - 6b}}{{2b}}  \frac{{1 - 12b}}{{2b}}\)   . . . . . is

• 1] 2b
• 2] -2b
• 3] 3
• 4] -3

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 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

A boy agrees to work at the rate of one rupee on the first day, two rupees on the second day, and four rupees on third day and so on. How much will the boy get if he started working on the 1st of February and finishes on the 20th of February?

• 1] 220
• 2] 220 -1
• 3] 219 -1
• 4] 219
• 5] None of these

The nth term of an A.P., the sum of whose n terms is Sn, is

• 1] Sn + Sn - 1
• 2] Sn - Sn - 1
• 3] Sn + Sn + 1
• 4] Sn - Sn + 1

The 7th and 21st terms of an AP are 6 and -22 respectively. Find the 26th term

• 1] -34
• 2] -32
• 3] -12
• 4] -10
• 5] -16

What is the sum of the first 13 terms of an arithmetic progression if the first term is -10 and last term is 26?

• 1] 104
• 2] 140
• 3] 84
• 4] 98

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