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1. The nth term of an arithmetic progression is given by

A. a + (n-1)d B. a - (n-1)d C. a + nd D. a - nd

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2. The sum of the first n terms of an arithmetic progression is given by

A. n/2[2a + (n-1)d] B. n[2a + (n-1)d] C. n/2[2a - (n-1)d] D. n[2a - (n-1)d]

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3. The sum of the first n natural numbers is

A. n(n+1)/2 B. n^2 C. n(n-1)/2 D. n^2/2

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4. The nth term of a geometric progression is given by

A. ar^(n-1) B. ar^n C. ar^(n+1) D. ar^2

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5. The sum of the first n terms of a geometric progression is given by

A. a(1-r^n)/(1-r) B. a(r^n-1)/(r-1) C. a(1-r^n)/(r-1) D. a(r^n-1)/(1-r)

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6. If the sum of an infinite geometric progression is 10 and the first term is 5, the common ratio is

A. 1/2 B. 1/3 C. 1/4 D. 2

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7. The arithmetic mean of 7 and 13 is

A. 9 B. 10 C. 11 D. 12

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8. The harmonic mean of 12 and 18 is

A. 10 B. 12 C. 13.5 D. 15

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9. The sum of the squares of the first n natural numbers is

A. n(n+1)(2n+1)/6 B. n^2(n+1)^2/4 C. n(n-1)(2n-1)/6 D. n^3

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10. The number of terms in the sequence 2, 5, 8, ..., 50 is

A. 16 B. 17 C. 18 D. 15

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11. The geometric mean of 4 and 16 is

A. 10 B. 8 C. 6 D. 12

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12. If a, b, c are in arithmetic progression, then b is equal to

A. (a+c)/2 B. (a+c) C. 2(a+c) D. a/c

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13. The nth term of a harmonic progression corresponding to an arithmetic progression is

A. 1/(a + (n-1)d) B. 1/(a - (n-1)d) C. (a + d)/(n-1) D. a/(n-1)

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14. The sum of an infinite geometric progression with first term a and common ratio r is

A. a/(1-r) B. ar C. a/(r-1) D. ar^n

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15. If the sum of the first 20 terms of an arithmetic progression is 400 and the first term is 5, the common difference is

A. 1 B. 2 C. 3 D. 4

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16. The sum of the first n terms of the series 1 + 4 + 9 + 16 + ... is given by

A. n(n+1)(2n+1)/6 B. n^2(n+1)^2/4 C. n(n-1)(2n-1)/6 D. n^3

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17. The sum of the cubes of the first n natural numbers is given by

A. (n(n+1)/2)^2 B. n(n+1)(2n+1)/6 C. n^2(n+1)^2 D. n(n-1)/2

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18. If the nth term of a sequence is given by a_n = 5n - 3, the sequence is

A. arithmetic progression B. geometric progression C. harmonic progression D. none of these

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19. The sum of the first n odd natural numbers is

A. n^2 B. 2n C. n(n+1) D. n(n-1)

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20. The product of three consecutive terms of a geometric progression is 64, and the terms are in ascending order. The terms are

A. 2, 4, 8 B. 4, 8, 16 C. 1, 8, 64 D. 8, 4, 2