## Odd Man Out and Series Formula

All time problem creating section of the exam is consider as Odd Man Out and Series. To make good combination with such type of questions
ejobhub team is going to tell the Odd Man Out and Series Formula for those students who are preparing for any competitive exam. ‘Quantitative Aptitude’ of any exam consists of questions regarding reasoning, Odd Man Out and Series Formula, Distance formulas and many more. Such participants who have remind all the necessary formulas, Shortcuts and problem tricks for these types of the questions they can get correct answer soon.

Those students who are not from math’s side they will face difficulty to solve all the questions. Short tricks help the aspirants to complete the question paper on given time. To score good marks in any of the post competitive / educational exams candidates will have to learn all the given formulas and important topics to give proper answer to series formula related questions. Questions asked in aptitude section are very easy so don’t take too much time in it. Apply the correct formula, write the correct digits and don’t get confused in similar type of questions. More details in association with Odd man out and series formula with suitable examples and solved problems are given below. All the best!!

Shortcuts to solve Problems: To complete the question paper on a given time period, you just need two thinks i.e. speed and accuracy. Take a look on formulas and examples that are mentioned below:

Series Formula: The terms or elements follow a definite law in series but it cannot be generalized. You should know about what is the definite relationship between numbers which make the set of given terms in series. Addition, subtraction, multiplication, division, transposition of terms and series generally form such series. The different questions asked may depend upon the following:

Odd number/Even number/Prime numbers: The series may consist of odd numbers /even numbers or prime numbers except one number, which will be the odd man out. Hence, before solving numerical on this topic must revise all basic concepts.

Perfect squares/Cubes:
Squares: 9, 16, 49, 81 ….
Cubes: 27, 64, 125, 216 ….

Multiple of numbers: The series contains numbers which are multiple of different numbers.
Example: 4, 8, 12, 16, 20….
Numbers in A.P./G.P.
Geometric progression: x, xr, xr3, xr4
Arithmetic progression: x, x + y, x + 2y, x + 3y are said to be in A.P.
The terms in series may be arithmetic or geometric progression.

Difference or sum of numbers: The difference between two consecutive numbers may increase or decrease

Cumulative series: In this type, the third number is the addition of previous two numbers.

Example: 2, 4, 6, 10, 16, 26 ……

Important Illustrations
Problem 1:
1)    13
2)    23
3)    33
4)    43
5)    53
Solution: Check these numbers. Have you observed any logic? Every number from the above list has 10 numbers difference from it's previous numbers. Great, we find one... But that's not the logic. So check whether the numbers are prime or not. So, here... all the given numbers are prime, except the number 33 (it is a composite number). So Option 3 is the answer.

Problem 2:
1)    176
2)    231
3)    572
4)    473
5)    653
Solution: Check the above numbers carefully. You can't find the correct answer by applying the first 2 steps. So here try to find out the logic... If you observe closely, you will find out that the middle number is the sum of the first and the last numbers. Check once....
1)    176
2)    231
3)    572
4)    473
5)    653
But you are not getting middle number in 5th Option (As 6+3 = 9, not 5). So this is the correct answer.

Problem 3:
1)    123
2)    246
3)    147
4)    368
5)    159
Solution: Here also we tried all the steps but no answer. Hey wait; have you tried the above logic??  Let's try
1)    1+3 = 4 (but the middle number is 2)
2)    2+6 = 8 (but the middle number is 4)
3)    1+7 = 8 (but the middle number is 4)
4)    3+8 = 11 (but the middle number is 6)
5)    9+1 = 10 (but the middle number is 5)
Not worked

Now see whether we can find anything with the newly obtained numbers....
4, 8, 8, 11, 10.... No relation.. But you could find out that one number except all are even numbers... So, may be this is our answer...
Or if you want to go further, you can get another logic... Just divide these numbers with 2.
1)    4/2 = 2
2)    8/2 = 4
3)    8/2 = 4
4)    11/2 = 5.5
5)    10/2 = 5
So, here.. Except Option 4...  For remaining numbers, the middle number is the half of the total of remaining two numbers.

Note: If you can't get answer with above step, then you should experiment with different numbers and different mathematical operations.

Problem 4:
1)    29: 812
2)    37: 1332
3)    45: 1980
4)    48: 2256
5)    51: 2551
If they ask question in the above format, then it means, there should be some relationship between the first and second number.

Solution:
Note: If you can't find any visible difference, then better to find out Squares.
1)    292 = 841 (but given number is 812)
2)    372 = 1369 (but the given number is 1332)
3)    452 = 2025 (but the given number is 1980)
4)    482= 2304 (but the given number is 2256)
5)    512 = 2601 (but the given number is 2551)
So squares are not matching with the numbers. But if you closely observe, you can see some similarities among these numbers. So, find out the difference, so that we could find some clue
1)    841-812 = 29 (First Number)
2)    1369-1332 = 37 (First Number)
3)    2025-1980 = 45 (First Number)
4)    2304-2256 = 48 (First Number)
5)    2601-2551 = 510 (Not the First Number)
So, Option 5 is the odd one.

Problem 5:
1)    126
2)    72
3)    135
4)    171
5)    162

Solution: At first glance we are unable to find any clues. So, check the interrelationships among these numbers (if any).
Note: People tend to mark Option 2 (72) as the answer because it consist only two numbers where as in remaining options the numbers are three. But please keep in mind that now a day they are not asking questions with such a simple logic.

At a close observation, you can find that the total of the given numbers is 9
1)    1+2+6 = 9
2)    7+2 = 9
3)    1+3+5 = 9
4)    1+7+1 = 9
5)    1+6+2 = 9
So, there might be something with this 9.

Let's subtract this 9 with the given number...
1)    126-9 = 117
2)    72-9 = 63
3)    135-9 = 126
4)    171-9 = 162
5)    162-9 = 153
You could find out some relation between option 4 and 5. But it's not enough.... So let's try division
1)    126/9 = 14
2)    72/9 = 8
3)    135/9 = 15
4)    171/9 = 19
5)    162/9 = 18
From the above answers, you can clearly say that 19 (Option 4) is a Prime Number. Where remaining numbers are not.

Problem 6:
1)    48-134
2)    65-185
3)    128-374
4)    56-158
5)    81-223
Solution: With a close observation you can see that the second number is almost nearer to the three times of the first number.
1)    40 x 3 = 120 (given number is 134)
2)    60 x 3 = 180 (given number is 185)
3)    120x 3 = 360 (given number is 374)
4)    50 x 3 = 150 (given number is 158)
5)    80x 3 = 240 (given number is 223)

So, there should be some logic behind it

Multiply first numbers with 3
1)    48x3 = 144 (difference between result and second number is 144-134 = 10)
2)    65x3 = 195 (195-185 = 10)
3)    128x3 = 384 (384-374 = 10)
4)    56x3 = 168 (168-158 = 10)
5)    81x3=243 (243-223= 20)
So, Option 5 is the answer.

Problem 7:
1)    25-630
2)    36-1312
3)    16-260
4)    9-84
5)    49-2408

Solution:
1)    252=625 (625+5 = 630)
2)    362=1296 (1296+16 = 1312)
3)    162 = 256 (256+4 = 260)
4)    92 = 81 (81+3 = 84)
5)    492 = 2401 (2401+7=2408)
So, here the odd one is Option 2

NOTE: So guys, finally you can qualify in the odd man out and serious.

Take a Look on Below Table