# Series Questions

Q:

In the following question, various terms of an alphanumerical series are given with one or more terms missing as shown by (?).Choose the missing terms out of the given alternatives. 2Z5, 7Y7, 14X9, 23W11, 34V13, ?

 A) 47U15 B) 47V14 C) 45U15 D) 27U24

Explanation:

The first numbers increase by 5, 7, 9, 11....
The letters move one step backward.
The last numbers are consecutive odd numbers.

160 7429
Q:

1, 2, 3, 10, ?, 9802

 A) 99 B) 199 C) 299 D) 999

Explanation:

$\inline&space;\fn_cm&space;2=1^{2}+1;\:&space;3=2^{2}-1;\:&space;10=3^{2}+1$

$\inline&space;\fn_cm&space;\therefore&space;\:&space;?=10^{2}-1=99$

127 4265
Q:

Find out the wrong term in the series 2, 5, 10, 50, 500, 5000

 A) 5000 B) 500 C) 10 D) 50

Explanation:

Each term of the series is the product of the preceding two terms
So, 5000 is wrong and it must be replaced by (500*50) = 25000

169 3868
Q:

Find out the wrong term in the series 2, 3, 4, 4, 6, 8, 9, 12, 16

 A) 9 B) 12 C) 16 D) 8

Explanation:

The given sequence is a combination of three series:
i)1st, 4th, 7th terms i.e, 2, 4, 9
ii)2nd, 5th, 8th terms i.e, 3, 6, 12
iii)3rd, 6th, 9th terms i.e, 4, 8, 16
In each one of i, ii, iii, each term is twice the preceding term.
So, 9 is wrong and must be replaced by (4*2) = 8

49 3419
Q:

Find the missing number in the series?

4, 18, ?, 100, 180, 294, 448

 A) 48 B) 50 C) 58 D) 60

Explanation:

$\inline 2^3-2^2=8-4=4$

$\inline 3^3-3^2=27-9=18$

$\inline 4^3-4^2=64-16=48$

$\inline 5^3-5^2=125-25=100$

$\inline 6^3-6^2=216-36=180$

$\inline 7^3-7^2=343-49=294$

$\inline 8^3-8^2=512-64=448$

$\therefore ?=48$