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Sequences and Series MCQs

1. The nth term of an A.P. whose 1st term is „a‟ and common difference is „d‟ is:

(A) 2a + (n + 1)d


(B) a + (n + 1)d


(C) a + (n – 1)d


(D) a + (d – 1)n




2. The nth term of an A.P. 1, 4, 7, …… is:

(A) 17


(B) 19


(C) 21


(D) 23




3. If a, b, c are in A.P. then:

(A) b – a = c – b


(B) b/c = a/b


(C) a + b = b + c


(D) a/b = c/a




4. The 10th term of 7, 17, 27, …… is:

(A) 97


(B) 98


(C) 99


(D) 100




5. The sum of n terms of an A.P. with „a‟ as 1st term and „d‟ as common difference is:

(A) n/2 [a + (n – 1)d]


(B) n/2 [2a + (n – 1)d]


(C) n/2 [a + (n + 1)d]


(D) n/2 [2a – (n – 1)d]




6. Arithmetic mean between x–3 and x+3 is:

(A) x


(B) 2x


(C) 3


(D) –3




7. If Sn = n² + n + 1 then its 4th term will be:

(A) 21


(B) 40


(C) 41


(D) 101




8. Arithmetic mean between –7 and 7 is:

(A) 7/2


(B) –7/2


(C) 0


(D) 14




9. The sum of the series 1 + 2 + 3 + …… + 100 is:

(A) 100


(B) 5000


(C) 5050


(D) 500




10. The nth term of a G.P a, ar, ar², …… is:

(A) ar²


(B) arn+1


(C) a r^(n–1)


(D) arn–1




11. The 5th term of a G.P 1, 1/2, 1/4, …… is:

(A) 1/8


(B) –1/8


(C) 1/16


(D) 1/32




12. The 6th term of G.P 1, 2, 4, …… is:

(A) 4


(B) 8


(C) 16


(D) 32




13. The G.M. between a and b is:

(A) ±√(ab)


(B) ab


(C) ±ab


(D) √(ab)




14. If x, y, z are in G.P. then:

(A) 2y = x + z


(B) 2y = xz


(C) y² = xz


(D) z² = xy




15. Geometric mean between 3 and 27 is:

(A) –9


(B) 12


(C) 15


(D) ±9




16. The sum of n terms of a geometric series a + ar + ar² + ……; |r| < 1 is:

(A) (ar^(n–1))/(1–r)


(B) a(1–r^n)/(1–r)


(C) (ar^(n+1))/(1–r)


(D) a(r–1)/(1–r)




17. The sum of 6 terms of the series 1 + 2 + 4 + …… is:

(A) 63


(B) 64


(C) 65


(D) 66




18. The sum of 5 terms of the series 1 – 2 + 4 …… is:

(A) 16


(B) 11


(C) –11


(D) –16




19. The sum of infinite terms of a G.P. a, ar, ar², …… if |r| < 1 is:

(A) a/(1–r)


(B) a(1–r^n)/(1–r)


(C) arn–1


(D) None of these




20. The sum of infinite geometric series 1 + 1/3 + 1/9 + …… is:

(A) 3/2


(B) –3/2


(C) 2/3


(D) –2/3




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