Overview: Logical Sequence Notes | Study CSAT Preparation for UPSC CSE - UPSC

Question 1: Find the missing letters in the pattern:

E_G_EFF_E_FG_FG_EF
(a) GFGEEE
(b) FGGGEF
(c) FGGEEG
(d) EGFEFG

Correct Answer is Option (c)
The series follows, +1,+1,+0 addition pattern.
So going by options, we get Option C to be correct.

_CAM_AMC_M_A_CAM
(a) CMAMC
(b) MACAM
(c) MCAMC
(d) MCACM

Correct Answer is Option (d)

This is a Series with MCA blocks repreated.
So, Our series must be
MCA MCA MCA MCA MCA M
Going by Options, We see Option D is correct

Question 3: Find the wrong number in the following series 
6,15,30,75,150,375,750
(a) 150
(b) 75
(c) 375
(d) 750

Correct Answer is Option (a)
This series follows the rule of *2 and *2+ last term.
15*2 =30
30*2 +15= 75
75*2 = 150.
Thus, 150 is the wrong term.

Question 4: What will be the next term in? 
ZAM, YBL, ----, WDJ, VEI
(a) XCK
(b) UFH
(c) ZAC
(b) PFD

Correct Answer is Option (a)
Look at the middle term.
We see the following Series.
A B C D E
Thus C is missing.
Going by options, We get A to be correct.

Question 5:  What will be the next term in? 
G, T, I, R, K, P, ___,___
(a) M,N
(b) O,P
(c) Q,R
(d) S,T

Correct Answer is Option (a)
In the number System of the digits, we see the series relates to an alternating +2,-2 series.
Number the letters, we get the following : 7,20,9,18,11,16. So the next two terms will be 13th and 14th term. Which are : M and N
Thus, Option A.

Correct Answer is Option (b)
The next term of the series is denoted by adding consecutive odd terms starting from 3
3+3=6
6+5 =11
11+7=18
18+9=27
27+11 =38
Since we have 29 in place of 27. It is the wrong term

Question 7: Find the wrong number in the given series?
9, 28, 65, 126, 217, 344, 213
(a) 65
(b) 126
(c) 217
(d) 213

Correct Answer is Option (d)
The series is an increasing series.
213 the last term is a smaller term that the previous one.
Thus it is Wrong.

Question 8: Arrange the words given below in a meaningful sequence.

1. Rainbow   2. Rain   3. Sun   4. Happy   5. Child     

(a)    4, 2, 3, 5, 1

(b)    2, 3, 1, 5, 4

(c)    4, 5, 1, 2, 3

(d)    2, 1, 4, 5, 3

Correct Answer is Option (b)

The correct order is :

Rain(2)  →  Sun(3)  →  Rainbow(1)  →  Child(5)  →  Happy(4)

Question 9: Arrange the words given below in a meaningful sequence.

1. Probation    2. Interview    3. Selection

4. Appointment    5. Advertisement    6. Application

(a)   5, 6, 3, 2, 4, 1

(b)   5, 6, 4, 2, 3, 1

(c)   5, 6, 2, 3, 4, 1

(d)   6, 5, 4, 2, 3, 1

Correct Answer is Option (c)

The correct order is :

Advertisement(5)  →  Application(6) →  Interview(2) →  Selection(3)  →  Appointment(4) →  Probation(1)

Question 10: Find the missing series.

G2X, J4V, M8T, ?, S32P

(a) N64S
(b) P16R  
(c) Q16R
(d) P8S

Correct Answer is Option (b)

Explanation:

G + 3 = J + 3 = M + 3 = P + 3 = S

2 * 2 = 4 * 2 = 8 * 2 = 16 * 2 = 32

X - 2 = V - 2 = T - 2 = R - 2 = P