The Logical Reasoning (LR) section tests your ability to analyze the logical foundations of a given argument. While knowledge of some formal logic principles can be helpful on some Logical Reasoning questions, you certainly don’t need prior training in formal logic in order to succeed on the LR section. Rather, your success will be dictated almost entirely by your ability to read effectively & critically. Much of this booklet will be dedicated to building your reading skills in the context of LR questions.
NUMBER SERIES
CATEGORY-1
Number series questions measure our ability to reason without words. To answer
these questions, we must determine the pattern of the numbers in each series before we
are able to choose which number comes next. These questions involve only simple arithmetic.
Although most number series items progress by adding or subtracting, some questions involve
simple multiplication or division. In each series, look for the DEGREE AND DIRECTION OF
CHANGE between the numbers. In other words, do the numbers increase or decrease, and by
how much?
1. Look at this series: 2, 1, (1/2), (1/4), … What number should come next?
A. (1/3)
B. (1/8)
C. (2/8)
D. (1/16)
Answer: Option B
Explanation: This is a simple division series; each number is one-half of the previous number.
In other terms to say, the number is divided by 2 successively to get the next result.
4/2 = 2
2/2 = 1
1/2 = 1/2
(1/2)/2 = 1/4
(1/4)/2 = 1/8 and so on.
2. Look at this series: 7, 10, 8, 11, 9, 12, … What number should come next?
A. 7
B. 10
C. 12
D. 13
Answer: Option B
Explanation: This is a simple alternating addition and subtraction series. In the first pattern,
3 is added; in the second, 2 is subtracted.
3. Look at this series: 36, 34, 30, 28, 24, … What number should come next?
A. 20
B. 22
C. 23
D. 26
Answer: Option B
Explanation: This is an alternating number subtraction series. First, 2 is subtracted, then 4,
then 2, and so on.
4. Look at this series: 22, 21, 23, 22, 24, 23, … What number should come next?
A. 22
B. 24
C. 25
D. 26
Answer: Option C
Explanation: In this simple alternating subtraction and addition series; 1 is subtracted, then
2 is added, and so on.
5. Look at this series: 53, 53, 40, 40, 27, 27, … What number should come next?
A. 12
B. 14
C. 27
D. 53
Answer: Option B
Explanation: In this series, each number is repeated, and 13 is subtracted to arrive at the
next number.
6. Look at this series: 21, 9, 21, 11, 21, 13, 21, … What number should come next?
A. 14
B. 15
C. 21
D. 23
Answer: Option B
Explanation: In this alternating repetition series, the random number 21 is interpolated every
other number into an otherwise simple addition series that increases by 2, beginning with
the number 9.
7. Look at this series: 58, 52, 46, 40, 34, … What number should come next?
A. 26
B. 28
C. 30
D. 32
Answer: Option B
Explanation: This is a simple subtraction series. Each number is 6 less than the previous
number.
8. Look at this series: 3, 4, 7, 8, 11, 12, … What number should come next?
A. 7
B. 10
C. 14
D. 15
Answer: Option D
Explanation: This alternating addition series begins with 3; then 1 is added to give 4; then 3
is added to give 7; then 1 is added, and so on.
9. Look at this series: 8, 22, 8, 28, 8, … What number should come next?
A. 9
B. 29
C. 32
D. 34
Answer: Option D
Explanation: This is a simple addition series with a random number, 8, interpolated as every
other number. In the series, 6 is added to each number except 8, to arrive at the next
number.
10.Look at this series: 31, 29, 24, 22, 17, … What number should come next?
A. 15
B. 14
C. 13
D. 12
Answer: Option A
Explanation: This is a simple alternating subtraction series, which subtracts 2, then 5.
11.Look at this series: 1.5, 2.3, 3.1, 3.9, … What number should come next?
A. 4.2
B. 4.4
C. 4.7
D. 5.1
Answer: Option C
Explanation: In this simple addition series, each number increases by 0.8.
12.Look at this series: 14, 28, 20, 40, 32, 64, … What number should come next?
A. 52
B. 56
C. 96
D. 128
Answer: Option B
Explanation: This is an alternating multiplication and subtracting series: First, multiply by 2
and then subtract 8.
13.Look at this series: 2, 4, 6, 8, 10, … What number should come next?
A. 11
B. 12
C. 13
D. 14
Answer: Option B
Explanation: This is a simple addition series. Each number increases by 2.
14.Look at this series: 201, 202, 204, 207, … What number should come next?
A. 205
B. 208
C. 210
D. 211
Answer: Option D
Explanation: In this addition series, 1 is added to the first number; 2 is added to the second
number; 3 is added to the third number; 4 is added to the fourth number; and go on.
15.Look at this series: 544, 509, 474, 439, … What number should come next?
A. 404
B. 414
C. 420
D. 445
Answer: Option A
Explanation: This is a simple subtraction series. Each number is 35 less than the previous
number.
16.Look at this series: 80, 10, 70, 15, 60, … What number should come next?
A. 20
B. 25
C. 30
D. 50
Answer: Option A
Explanation: This is an alternating addition and subtraction series. In the first pattern, 10 is
subtracted from each number to arrive at the next. In the second, 5 is added to each number
to arrive at the next.
17.Look at this series: 2, 6, 18, 54, … What number should come next?
A. 108
B. 148
C. 162
D. 216
Answer: Option C
Explanation: This is a simple multiplication series. Each number is 3 times more than the
previous number.
18.Look at this series: 5.2, 4.8, 4.4, 4, … What number should come next?
A. 3
B. 3.3
C. 3.5
D. 3.6
Answer: Option D
Explanation: In this simple subtraction series, each number decreases by 0.4.
19.Look at this series: 1000, 200, 40, … What number should come next?
A. 8
B. 10
C. 15
D. 20
Answer: Option A
Explanation: This is a simple division series. Each number is divided by 5.
20.Look at this series: 40, 40, 47, 47, 54, … What number should come next?
A. 40
B. 44
C. 54
D. 61
Answer: Option C
Explanation: Each number repeats itself and then increases by 7.
40, 40, 47, 47, 54, 54, 61, 61, 68, 68, 75, 75 … and so on. Therefore, 54 is the required
answer.
CATEGORY – 2
:: This set contains additional, and sometimes more difficult, number series
questions. Again, each question has a definite pattern. Some of the number series may be interrupted by a particular number that appears periodically in the pattern. For example, in the series 14, 16, 32, 18, 20, 32, 22, 24, 32, the number 32 appears as every third number.
Sometimes, the pattern contains two alternating series. For example, in the series 1, 5, 3, 7, 5, 9, 7, the pattern is add 4, subtract 2, add 4, subtract 2, and so on. Look carefully for the pattern, and then choose which pair of numbers comes next.
1) 28 25 5 21 18 5 14
A. 11 5
B. 10 7
C. 11 8
D. 5 10
E. 10 5
Answer: Option A
Explanation: This is an alternating subtraction series with the interpolation of a random
number, 5, as every third number. In the subtraction series, 3 is subtracted, then 4, then 3,
and so on.
2) 8 11 21 15 18 21 22
A. 25 18
B. 25 21
C. 25 29
D. 24 21
E. 22 26
Answer: Option B
Explanation: This is an alternating addition series, with a random number, 21, interpolated as every third number. The addition series alternates between adding 3 and adding 4. The number 21 appears after each number arrived at by adding 3.
3) 9 16 23 30 37 44 51
A. 59 66
B. 56 62
C. 58 66
D. 58 65
E. 54 61
Answer: Option D
Explanation: Here is a simple addition series, which begins with 9 and adds 7.
4) 2 8 14 20 26 32 38
A. 2 46
B. 44 50
C. 42 48
D. 40 42
E. 32 26
Answer: Option B
Explanation: This is a simple addition series, which begins with 2 and adds 6.
5) 9 11 33 13 15 33 17
A. 19 33
B. 33 35
C. 33 19
D. 15 33
E. 19 21
Answer: Option A
Explanation: In this alternating repetition series, a random number, 33, is interpolated every third number into a simple addition series, in which each number increases by 2.
6) 2 3 4 5 6 4 8
A. 9 10
B. 4 8
C. 10 4
D. 9 4
E. 8 9
Answer: Option D
Explanation: This is an alternating addition series with a random number, 4, interpolated as
every third number. In the main series, 1 is added, then 2 is added, then 1, then 2, and so
on.
7) 17 17 34 20 20 31 23
A. 26 23
B. 34 20
C. 23 33
D. 27 28
E. 23 28
Answer: Option E
Explanation: This is an alternating subtraction series with repetition. There are two different
patterns here. In the first, a number repeats itself; then 3 is added to that number to arrive
at the next number, which also repeats. This gives the series 17, 17, 20, 20, 23, and so on.
Every third number follows a second pattern, in which 3 is subtracted from each number to
arrive at the next: 34, 31, 28.
8) 6 20 8 14 10 8 12
A. 14 10
B. 2 18
C. 4 12
D. 2 14
E. 14 14
Answer: Option D
Explanation: This is an alternating addition and subtraction series. In the first pattern, 2 is
added to each number to arrive at the next; in the alternate pattern, 6 is subtracted from
each number to arrive at the next.
9) 21 25 18 29 33 18
A. 43 18
B. 41 44
C. 37 18
D. 37 41
E. 38 41
Answer: Option D
Explanation: This is a simple addition series with a random number, 18, interpolated as every
third number. In the series, 4 is added to each number except 18, to arrive at the next
number.
10) 75 65 85 55 45 85 35
A. 25 15
B. 25 85
C. 35 25
D. 85 35
E. 25 75
Answer: Option B
Explanation: This is a simple subtraction series in which a random number, 85, is interpolated
as every third number. In the subtraction series, 10 is subtracted from each number to arrive
at the next.
11) 11 16 21 26 31 36 41
A. 47 52
B. 46 52
C. 45 49
D. 46 51
Answer: Option D
Explanation: In this simple addition series, each number is 5 more than the previous number.
12) 3 8 13 18 23 28 33
A. 39 44
B. 38 44
C. 38 43
D. 37 42
E. 33 38
Answer: Option C
Explanation: In this simple addition series, each number is 5 greater than the previous
number.
13) 84 78 72 66 60 54 48
A. 44 34
B. 42 36
C. 42 32
D. 40 34
E. 38 32
Answer: Option B
Explanation: In this simple subtraction series, each number is 6 less than the previous
number.
14) 20 20 17 17 14 14 11
A. 8 8
B. 11 11
C. 11 14
D. 8 9
E. 11 8
Answer: Option E
Explanation: This is a simple subtraction with repetition series. It begins with 20, which is
repeated, then 3 is subtracted, resulting in 17, which is repeated, and so on.
15) 61 57 50 61 43 36 61
A. 29 61
B. 27 20
C. 31 61
D. 22 15
E. 29 22
Answer: Option E
Explanation: This is an alternating repetition series, in which a random number, 61, is
interpolated as every third number into an otherwise simple subtraction series. Starting with
the second number, 57, each number (except 61) is 7 less than the previous number.
16) 9 12 11 14 13 16 15
A. 14 13
B. 18 21
C. 14 17
D. 12 13
E. 18 17
Answer: Option E
Explanation: This is a simple alternating addition and subtraction series. First, 3 is added,
then 1 is subtracted, then 3 is added, 1 subtracted, and so on.
17) 4 8 22 12 16 22 20 24
A. 28 32
B. 28 22
C. 22 28
D. 32 36
E. 22 26
Answer: Option C
Explanation: This is an alternating repetition series, with a random number, 22, interpolated
as every third number into an otherwise simple addition series. In the addition series, 4 is
added to each number to arrive at the next number.
18) 40 40 31 31 22 22 13
A. 13 4
B. 13 5
C. 4 13
D. 9 4
E. 4 4
Answer: Option A
Explanation: This is a subtraction series with repetition. Each number repeats itself and then
decreases by 9.
19) 1 10 7 20 13 30 19
A. 26 40
B. 29 36
C. 40 25
D. 25 31
E. 40 50
Answer: Option C
Explanation: Here, every other number follows a different pattern. In the first series, 6 is
added to each number to arrive at the next. In the second series, 10 is added to each number
to arrive at the next.
20) 10 20 25 35 40 50 55
A. 70 65
B. 60 70
C. 60 75
D. 60 65
E. 65 70
Answer: Option E
Explanation: This is an alternating addition series, in which 10 is added, then 5, then 10, and
so on.
CATEGORY3
Look carefully for the pattern, and then choose which pair of numbers comes next.
This set will give you additional practice dealing with number series questions.
1) 42 40 38 35 33 31 28
A. 25 22
B. B. 26 23
C. C. 26 24
D. D. 25 23
E. E. 26 22
Answer: Option C
Explanation: This is an alternating subtraction series in which 2 is subtracted twice, then 3
is subtracted once, then 2 is subtracted twice, and so on.
2) 6 10 14 18 22 26 30
A. 36 40
B. B. 33 37
C. C. 38 42
D. D. 34 36
E. E. 34 38
Answer: Option E
Explanation: This simple addition series adds 4 to each number to arrive at the next.
3) 8 12 9 13 10 14 11
A. 14 11
B. 15 12
C. 8 15
D. 15 19
E. 8 5
Answer: Option B
Explanation: This is an alternating addition and subtraction series, in which the addition of 4
is alternated with the subtraction of 3.
4) 36 31 29 24 22 17 15
A. 13 11
B. 10 5
C. 13 8
D. 12 7
E. 10 8
Answer: Option E
Explanation: This is an alternating subtraction series, which subtracts 5, then 2, then 5, and
so on.
5) 3 5 35 10 12 35 17
A. 22 35
B. 35 19
C. 19 35
D. 19 24
E. 22 24
Answer: Option C
Explanation: This is an alternating addition series, with a random number, 35, interpolated
as every third number. The pattern of addition is to add 2, add 5, add 2, and so on. The
number 35 comes after each “add 2” step.
6) 13 29 15 26 17 23 19
A. 21 23
B. 20 21
C. 20 17
D. 25 27
E. 22 20
Answer: Option B
Explanation: Here, there are two alternating patterns, with every other number following a
different pattern. The first pattern begins with 13 and adds 2 to each number to arrive at the
next; the alternating pattern begins with 29 and subtracts 3 each time.
7) 14 14 26 26 38 38 50
A. 60 72
B. 50 62
C. 50 72
D. 62 62
E. 62 80
Answer: Option B
Explanation: In this simple addition with repetition series, each number in the series repeats
itself, and then increases by 12 to arrive at the next number.
8) 44 41 38 35 32 29 26
A. 24 21
B. 22 19
C. 23 19
D. 29 32
E. 23 20
Answer: Option E
Explanation: This is a simple subtraction series, in which 3 is subtracted from each number
to arrive at the next.
9) 34 30 26 22 18 14 10
A. 8 6
B. 6 4
C. 14 18
D. 6 2
E. 4 0
Answer: Option D
Explanation: This is a simple subtraction series, in which 4 is subtracted from each number
to arrive at the next.
10) 32 31 32 29 32 27 32
A. 25 32
B. 31 32
C. 29 32
D. 25 30
E. 29 30
Answer: Option A
Explanation: This is an alternating repetition series. The number 32 alternates with a series
in which each number decreases by 2.
11) 7 9 66 12 14 66 17
A. 19 66
B. 66 19
C. 19 22
D. 20 66
E. 66 20
Answer: Option A
Explanation: This is an alternating addition series with repetition, in which a random number,
66, is interpolated as every third number. The regular series adds 2, then 3, then 2, and so
on, with 66 repeated after each “add 2” step.
12) 3 8 10 15 17 22 24
A. 26 28
B. 29 34
C. 29 31
D. 26 31
E. 26 32
Answer: Option C
Explanation: This is an alternating addition series that adds 5, then 2, then 5, and so on.
13) 4 7 26 10 13 20 16
A. 14 4
B. 14 17
C. 18 14
D. 19 13
E. 19 14
Answer: Option E
Explanation: Two patterns alternate here, with every third number following the alternate
pattern. In the main series, beginning with 4, 3 is added to each number to arrive at the
next. In the alternating series, beginning with 26, 6 is subtracted from each number to arrive
at the next.
14) 32 29 26 23 20 17 14
A. 11 8
B. 12 8
C. 11 7
D. 32 29
E. 10 9
Answer: Option A
Explanation: In this simple subtraction series, the numbers decrease by 3.
15) 16 26 56 36 46 68 56
A. 80 66
B. 64 82
C. 66 80
D. 78 68
E. 66 82
Answer: Option C
Explanation: Here, every third number follows a different pattern from the main series. In
the main series, beginning with 16, 10 is added to each number to arrive at the next. In the
alternating series, beginning with 56, 12 is added to each number to arrive at the next.
16) 2 44 4 41 6 38 8
A. 10 12
B. 35 32
C. 34 9
D. 35 10
E. 10 52
Answer: Option D
Explanation: Here, there are two alternating patterns, one addition and one subtraction. The
first starts with 2 and increases by 2; the second starts with 44 and decreases by 3.
17) 17 32 19 29 21 26 23
A. 25 25
B. 20 22
C. 23 25
D. 25 22
E. 27 32
Answer: Option C
Explanation: Here, there are two alternating patterns. The first begins with 17 and adds 2;
the second begins with 32 and subtracts 3.
18) 17 14 14 11 11 8 8
A. 8 5
B. 5 2
C. 8 2
D. 5 5
E. 5 8
Answer: Option D
Explanation: In this simple subtraction with repetition series, each number is repeated, then
3 is subtracted to give the next number, which is then repeated, and so on.
19) 10 34 12 31 14 28 16
A. 25 18
B. 30 13
C. 19 26
D. 18 20
E. 25 22
Answer: Option A
Explanation: Two patterns alternate here. The first pattern begins with 10 and adds 2 to each
number to arrive at the next; the alternating pattern begins with 34 and subtracts 3 each
time.
20) 11 14 14 17 17 20 20
A. 23 23
B. 23 26
C. 21 24
D. 24 24
E. 24 27
Answer: Option A
Explanation: This is a simple addition series with repetition. It adds 3 to each number to
arrive at the next, which is repeated before 3 is added again.