Class 10 Maths Chapter 5: Arithmetic Progressions MCQs with answers
10 multiple-choice questions on Arithmetic Progressions, each with its answer and the reason, written from the NCERT chapter. Open a question's solution to check your working; then take the free test to find your next chapter.
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Answer: (c) −6
d = a₂ − a₁ = 11 − 17 = −6. (6 subtracts the wrong way round.)
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Answer: (d) 130
a = 4, d = 9, so a₁₅ = 4 + 14 × 9 = 130. (139 uses a + 15d.)
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Answer: (d) −7, −2, 3, 8
For −7, −2, 3, 8 the differences are 5, 5, 5. The others: 4, 12, 36; 4, 5, 6; 3, 5, 7 are not fixed.
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Answer: (a) 820
S₂₀ = 20/2 [2 × 3 + 19 × 4] = 10 × 82 = 820.
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Answer: (a) 1830
Sₙ = n(n + 1)/2 = 60 × 61/2 = 1830. (3660 forgets to halve.)
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Answer: (c) −35
d = 5 − 9 = −4, so a₁₂ = 9 + 11 × (−4) = −35. (−39 is a + 12d; 53 drops the sign of d.)
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Answer: (a) its first term and its common difference
The terms are a, a + d, a + 2d, . . ., so both a and d are needed; either alone fixes nothing else.
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Answer: (b) −100
Here a = −4 and d = 0, so S₂₅ = 25/2 [2(−4) + 24 × 0] = −100.
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Answer: (b) 20th term
The kth term carries (k − 1) lots of d, so k − 1 = 19 and k = 20.
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Answer: (c) 29th
176 = 8 + (n − 1) × 6 gives n − 1 = 28, so n = 29. (28 forgets to add 1.)