Quiz Discussion

The sum of the first and third term of an arithmetic progression is 12 and the product of first and second term is 24, then first term is

• 1]

  4

• 2]

  1

• 3]

  8

• 4]

  6

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

• 1] 8th
• 2] 9th
• 3] 10th
• 4] 12th

The first and last term of an A.P. is a and l respectively. If S is the sum of all the terms of the A.P. and the common difference is given by \(\frac{{{l^2} - {a^2}}}{{k - \left( {l + a} \right)}}\)   then k = ?

• 1] S
• 2] 2S
• 3] 3S
• 4] None of these

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]

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

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 S1 is the sum of an arithmetic progression of ‘n’ odd number of terms and S2 is the sum of the terms of the series in odd places, then \(\frac{{{S_1}}}{{{S_2}}}\)

• 1]

  \(\frac{{2n}}{{n + 1}}\)

• 2]

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

• 3]

  \(\frac{{n + 1}}{{2n}}\)

• 4]

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

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

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

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. 92, 88, 84, 80, ...... is 0?

• 1]

  23

• 2]

  32

• 3]

  24

• 4]

  28