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

What is the sum of the first 17 terms of an arithmetic progression if the first term is -20 and last term is 28?

• 1] 68
• 2] 156
• 3] 142
• 4] 242

What is the sum of the first 9 terms of an arithmetic progression if the first term is 7 and last term is 55?

• 1] 219
• 2] 279
• 3] 231
• 4] 137

Find the n^th term of the following sequence :
5 + 55 + 555 + . . . . T_n

• 1]

   

  5(10ⁿ - 1) 

• 2]

   

  5ⁿ(10ⁿ - 1)

• 3]

  5/9×(10ⁿ−1)

     

• 4]

  (5/9)ⁿ×(10ⁿ−1)

If the first term of an A.P. is 2 and common difference is 4, then the sum of its 40 term is

• 1] 3200
• 2] 1600
• 3] 200
• 4] 2800

If the 7^th term of a H.P. is 1/10 and the 12^th term is 1/25, then the 20^th term is

• 1]

  1/41

• 2]

  1/45

• 3]

  1/49

• 4]

  1/37

If the sums of n terms of two arithmetic progressions are in the ratio \(\frac{{3n + 5}}{{5n + 7}}\)   then their nth terms are in the ration

• 1]

  \(\frac{{3n - 1}}{{5n - 1}}\)

• 2]

  \(\frac{{3n + 1}}{{5n + 1}}\)

• 3]

  \(\frac{{5n + 1}}{{3n + 1}}\)

• 4]

  \(\frac{{5n - 1}}{{3n - 1}}\)

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

What is the sum of the following series? -64, -66, -68, ......, -100

• 1] -1458
• 2] -1558
• 3] -1568
• 4] -1664

The sum of first n odd natural numbers in

• 1] 2n - 1
• 2] 2n + 1
• 3] n2
• 4] n2 - 1