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About Arithmetic & Geometric Progression — Class 10 ICSE

Find nth terms and sums of arithmetic and geometric progressions with applications. This topic is part of the ICSE Class 10 mathematics syllabus (chapter: Chapter 11). On this page you can practice 60 questions across three difficulty levels — 20 easy, 20 medium, and 20 hard — each with a visual step-by-step solution, plus a timed 10-question mastery test with a live leaderboard. Worked examples and sample questions from the topic are below.

Arithmetic & Geometric Progression — solved examples for Class 10 ICSE

Example 1easy

Which of the following is an Arithmetic Progression (AP)?

(i) 2,5,8,11,2, 5, 8, 11, \ldots (ii) 1,3,9,27,1, 3, 9, 27, \ldots (iii) 5,5,5,5,5, 5, 5, 5, \ldots
  1. A)Only (i)
  2. B)Only (ii)
  3. C)(i) and (iii)
  4. D)All three

Step-by-step solution

  1. (i) Differences:
    52=3,  85=3,  118=3 AP5-2=3,\; 8-5=3,\; 11-8=3 \quad \checkmark \text{ AP}
  2. (ii) Differences:
    31=2,  93=6× Not AP (it’s a GP)3-1=2,\; 9-3=6 \quad \times \text{ Not AP (it's a GP)}
  3. (iii) Differences:
    55=0,  55=0 AP with d=05-5=0,\; 5-5=0 \quad \checkmark \text{ AP with } d=0

Answer: (i) and (iii)

Example 2medium

The sum of the first 2020 terms of the AP 1,4,7,10,1, 4, 7, 10, \ldots is:
  1. A)590590
  2. B)570570
  3. C)610610
  4. D)550550

Step-by-step solution

  1. S20S_{20}:
    =202[2(1)+(201)(3)]=10[2+57]=10×59=590= \frac{20}{2}[2(1) + (20-1)(3)] = 10[2 + 57] = 10 \times 59 = 590

Answer: 590590

Example 3hard

If a1,a2,a3,a_1, a_2, a_3, \ldots is an AP with common difference dd, then a1+a3+a5++a2n1a_1 + a_3 + a_5 + \ldots + a_{2n-1} equals:
  1. A)na1+n(n1)dna_1 + n(n-1)d
  2. B)nanna_n
  3. C)n(a1+a2n1)/2n(a_1 + a_{2n-1})/2
  4. D)na1+n2dna_1 + n^2 d

Step-by-step solution

  1. Odd terms: a1,a3,a5,a_1, a_3, a_5, \ldots form AP with first term a1a_1, c.d. =2d= 2d, nn terms
  2. Sum:
    =n2[2a1+(n1)(2d)]=n[a1+(n1)d]=na1+n(n1)d= \frac{n}{2}[2a_1 + (n-1)(2d)] = n[a_1 + (n-1)d] = na_1 + n(n-1)d

Answer: na1+n(n1)dna_1 + n(n-1)d

Practice questions on Arithmetic & Geometric Progression

  1. Q1.easy

    The common difference of the AP 7,11,15,19,7, 11, 15, 19, \ldots is:
    1. A)33
    2. B)44
    3. C)77
    4. D)4-4
    Show answer

    Answer: 44

    Hint: Common difference = second term minus first term.

  2. Q2.easy

    The nnth term of an AP with first term aa and common difference dd is:
    1. A)a+nda + nd
    2. B)a+(n1)da + (n-1)d
    3. C)a×dn1a \times d^{n-1}
    4. D)a×dna \times d^n
    Show answer

    Answer: a+(n1)da + (n-1)d

    Hint: The first term has 0 differences added, the second has 1, the nth has (n-1).

  3. Q3.easy

    Find the 1010th term of the AP 3,7,11,15,3, 7, 11, 15, \ldots
    1. A)3939
    2. B)3737
    3. C)3535
    4. D)4141
    Show answer

    Answer: 3939

    Hint: Use an=a+(n1)da_n = a + (n-1)d with a=3a = 3, d=4d = 4, n=10n = 10.

  4. Q4.medium

    If the 55th term of an AP is 1919 and the 1010th term is 3434, find the first term.
    1. A)55
    2. B)77
    3. C)33
    4. D)99
    Show answer

    Answer: 77

    Hint: a5=a+4d=19a_5 = a + 4d = 19 and a10=a+9d=34a_{10} = a + 9d = 34. Subtract to find d first.

  5. Q5.medium

    The 44th term of a GP is 2424 and the 77th term is 192192. Find the common ratio.
    1. A)22
    2. B)33
    3. C)44
    4. D)12\frac{1}{2}
    Show answer

    Answer: 22

    Hint: a7a4=r3\frac{a_7}{a_4} = r^3.

  6. Q6.medium

    Find the sum: 1+3+5+7++991 + 3 + 5 + 7 + \ldots + 99.
    1. A)25002500
    2. B)24502450
    3. C)25502550
    4. D)24002400
    Show answer

    Answer: 25002500

    Hint: This is an AP of odd numbers. Find n first, then use the sum formula.

  7. Q7.hard

    If the sum of the first pp terms of an AP is equal to the sum of the first qq terms (where pqp \neq q), then the sum of the first (p+q)(p+q) terms is:
    1. A)p+qp + q
    2. B)pqpq
    3. C)00
    4. D)2(p+q)2(p+q)
    Show answer

    Answer: 00

    Hint: Set Sp=SqS_p = S_q and use the sum formula. Then find Sp+qS_{p+q}.

  8. Q8.hard

    The ratio of the sums of nn terms of two APs is (7n+1):(4n+27)(7n+1):(4n+27). The ratio of their 1111th terms is:
    1. A)4:34:3
    2. B)148:111148:111
    3. C)71:5571:55
    4. D)7:47:4
    Show answer

    Answer: 4:34:3

    Hint: The ratio of nth terms = the ratio of sums evaluated at mm where ama_m = a11a_{11}, i.e., at n=21n = 21.

  9. Q9.hard

    If SnS_n denotes the sum of nn terms of an AP whose rrth term is ara_r, then Sn2Sn1+Sn2S_n - 2S_{n-1} + S_{n-2} equals:
    1. A)ana_n
    2. B)2an2a_n
    3. C)dd
    4. D)00
    Show answer

    Answer: 00

    Hint: SnSn1=anS_n - S_{n-1} = a_n and Sn1Sn2=an1S_{n-1} - S_{n-2} = a_{n-1}. So the expression = anan1a_n - a_{n-1}... but wait, is it?

These are 9 of the 60 questions available for Arithmetic & Geometric Progression. Start practicing above to unlock visual solutions, AI coaching, and the topic leaderboard — completely free.