Practice MCQ Questions and Answer on Series Completion

1.

Choose the missing terms out of the given alternatives : UPI, ?, ODP, MBQ, IAW

• (A) RHJ
• (B) SHJ
• (C) SIJ
• (D) THK

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 1st letter : U - 2 = S - 4 = O - 2 = M - 4 = I 2nd letter : P - 8 = H - 4 = D - 2 = B - 1 = A 3rd letter : I + 1 = J + 6 = P + 1 = Q + 6 = W

2.

One term in the number series is wrong. Find out the wrong term.
5, 27, 61, 122, 213, 340, 509

• (A) 27
• (B) 61
• (C) 122
• (D) 509

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 The terms of the series are (23 - 3), (33 - 3), (43 - 3), (53 - 3), (63 - 3), (73 - 3), (83-3). So, 27 is wrong and must be replaced (33 - 3) i.e. 24.

3.

3, 7, 23, 95, ?

• (A) 62
• (B) 128
• (C) 479
• (D) 575

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 The pattern is x 2 + 1, x 3 + 2, x 4 + 3,..... So, missing term = 95 x 5 + 4 = 479.

4.

One term in the number series is wrong. Find out the wrong term.
3, 7, 15, 39, 63, 127, 255, 511

• (A) 15
• (B) 39
• (C) 63
• (D) 127

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 The correct pattern is x 2 + 1. So, 39 is wrong and must be replaced by (15 x 2 + 1) i.e. 31.

5.

Choose the missing terms out of the given alternatives.
AYD, BVF, DRH, ?, KGL

• (A) FMI
• (B) GMJ
• (C) GLJ
• (D) HLK

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6.

Choose the missing terms out of the given alternatives.
DHL, PTX, BFJ, ?

• (A) CGK
• (B) KOS
• (C) NRV
• (D) RVZ

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7.

Choose the missing terms out of the given alternatives.
AZ, CX, FU, ?

• (A) IR
• (B) IV
• (C) JQ
• (D) KP

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8.

One term in the number series is wrong. Find out the wrong term.
6, 15, 35, 77, 165, 221

• (A) 35
• (B) 77
• (C) 165
• (D) 15

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 The terms of the series are products of two consecutive prime numbers i.e. (2 x 3), (3 x 5), (5 x 7), (7 x 11),..... So, 165 is wrong and must be replaced by (11 x 13) i.e. 143.

9.

One term in the number series is wrong. Find out the wrong term.
380, 188, 92, 48, 20, 8, 2

• (A) 8
• (B) 20
• (C) 48
• (D) 188

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 The correct pattern is - 192, - 96, - 48, - 24, - 12, - 6. So, 48 is wrong and must be replaced by (92 - 48) i.e. 44.

10.

0, 2, 3, 5, 8, 10, 15, 17, 24, 26, ?

• (A) 28
• (B) 30
• (C) 32
• (D) 35

Show Answer

 The given sequence is a combination of two series : I. 0, 3, 8, 15, 24, ? and II. 2, 5, 10, 17, 26 The pattern in each one of I and II is + 3, + 5, + 7, + 9, ..... So, missing term = 24 + 11 = 35.