0Earlier, number series were asked in the form of missing number. But, seeing some recent exams, it has been found that the latest pattern of number series is to identify wrong numbers given in the series. So, we will discuss this latest pattern. This latest pattern is nothing but an advanced pattern of missing numbers. If you know the basics of number series, then it will be easier for you.
You Must Learn Squares Of Numbers Upto 40 And Cubes Of Numbers Upto 20.
Note: In the wrong number series, the pattern of series will always be wrong immediately before and after of the wrong number. There are uncountable numbers of series because series is an imagination. Some of the important series pattern are discussed below:
1. Based on addition and subtraction. 4, 9, 14, 18, 24, 29 the difference of two successive numbers is 5 but difference of 18 and 14 is 4, difference of 24 and 18 is 6. So, wrong number is 18. Correct answer is 19. 2. Based on multiplication and division. 18, 28, 40.5, 60.75, 91.125, 136.6875.
Solution: Problem with this type of series is how to identify these types of series. Check the difference between successive numbers. ----10----12.5----20.25----30.375----45.5625 we can see that the difference is half of the previous number. 10 is not the half of 18 and 12.5 is not the half of 28. So, 28 is wrong and correct number is 27. 3. Based on square and cube. 8 27 125 512 1331 2197 Solution: 23 = 8, 33 = 27, 53 = 125, 83 = 512, 113 = 1331, 133 = 2197. In this all are cubes of number 2, 3, 5, 8, 11, 13. These numbers are prime numbers except 8 and from 2 to 11, 7 is also prime number which is missing. In place of 83, there should be 73 i.e. 343 4. Based on mix pattern. 6, 11, 21, 40, 81, 161. This series could have followed two patterns. Pattern 1: difference is –5---10----19-----41---80. Successive difference is 2 times of previous one. But 19 and 41 is not following the pattern. We can guess that something is wrong in this term if we want 20 and 40, we have to replace 40 by 41. Hence 40 is wrong. Pattern 2: 6 6 x 2-1 = 11 11 x 2-1 = 21 21 x 2 -1 = 41 41 x 2 – 1 = 81 81 x 2 -1 = 161 Hence, 40 is wrong If you go through various types of pattern of wrong number series and have practiced them. You will not have any problem in solving the series. Now, we will discuss previous year asked questions based on number series.
Example 1: 12 12 18 45 180 1080 12285 In this series also there can be two pattern. Pattern 1 Pattern 2 12 x 1 = 12 12 x (1.5) = 18 18 x (1.5 +1) = 45 45 x (2.5+1.5) = 180 180 x (4+2.5) = 1170 1170 x (6.5+4) = 12285 12 x (1+0) = 12 12 x (1+.5) = 18 18 x (1.5+1) = 45 45 x (2.5+1.5) = 180 180 x (4+2) = 1080 1080 x (6+2.5) = 9180. So, if it follows pattern1, the wrong number in series is 1080 and if it follows pattern2, the wrong number in series is 12285. It depends on options given in exams.
Example 2: 7 5 7 17 63 ? (SBI PO Prelims 2016) Answer: 309 7x1 – 2 = 5 5x2 – 3 = 7 7x3 – 4 = 17 17 x 4 – 5 = 63 63 x 5 – 6 = 309
Example 3: 50…… 61 89 154 280 (SBI PO Prelims 2016) Answer : 52 50 + (13+1) = 52 52 + (23+1) = 61 61 + (33+1) = 89 89 + (43+1) = 154 154 + (53+1) = 280
Example 4: 17, 19, 25, 37, ......,87 (SBI PO Prelims 2016) Answer: 57 17 + 1 x 2 = 19 19 + 2 x 3 = 25 25 + 3 x 4 = 37 37 + 4 x 5 = 57 57 + 5 x 6 = 87
Example 5: 11, 14, 19, 28, 43, ? (SBI PO Prelims 2016) Answer: 66 3...5...9...15...23 2...4....6.......8 Answer 43+23= 66
Example 6: 26 144 590 1164 ? (SBI PO Prelims 2016) Answer: 1182 26 x 6 – 12 = 144 144 x 4 + 14 = 590 590 x 2 – 16 = 1164 1164 x 1 + 18 = 1182.
Example 7: 6 48 8 70 9 63 7 Find the wrong number? Answer: 9 x 7=63, 9 x 8 = 72, 8 x 6 = 48. So, 70 is wrong in this series
Example 8: 1,4,11,34,102,304,911 Answer: 102 Pattern of Series is 1 1 x 3 + 1 = 4 4 x 3 - 1 = 11 11 x 3 + 1 = 34 34 x 3 - 1 = 101 101 x 3 + 1 = 304 304 x 3 - 1 = 911.
Example 9: 1, 2, 12, 146, 2880, 86400, 3628800. Answer: 146 1 1 x 1 x 2 = 2 2 x 2 x 3=12 12 x 3 x 4 = 144 144 x 4 x 5 = 2880 2880 x 5 x 6 = 86400 86400 x 6 x 7 = 3628800
Example 10: 0,6,23,56,108,184,279 Answer: 108 13-20 = 1-1 =0 23-21 = 8-2 =6 33-22 = 27-4 = 23 43-23= 64-8 = 56 53-24= 125-16 = 109 63-25= 216-32 = 184 73-26= 343-64 =279
Example 11: 813,724,635,546,457,564,279 Answer : 564 Hundred place digit is decreasing by 1, tens place is increasing by 1 and unit place digit is also increasing by 1. But this pattern is not followed in 564. 368 should be there in place of 564.
Example 12: 0,4,19,48,100,180,294 Answer: 19 13 - 12 = 0 23 - 22 = 4 33 - 32 = 18 43 - 42= 48 53 - 52 = 100 63-62 = 180 73 - 72 = 294
Example 13: 3.2, 4.8, 2.4, 3.6, 1.6, 2.7 Answer : 1.6 3.2 x 1.5 = 4.8 4.8 ÷ 2 = 2.4 2.4 × 1.5 = 3.6 3.6 ÷ 2 = 1.8 1.8 x 1.5 = 2.4
Example 14: 2, 9, 24, 55, 117, 245 Answer : 117 2 x 2 + 5 = 9 9 x 2 + 6 = 24 24 x 2 + 7 = 55 55 x 2 + 8 = 118 118 x 2 + 9 = 245
Example 15: 109, 131, 209, 271, 341, 419 Answer: 131 112 - 12 = 109 132 - 14 = 155 152 - 16 = 209 172 - 18 = 271 192 - 20 = 341 212 - 22 = 419
Example 16: 6, 7, 27, 115, 513, 3069 Answer : 115 6 x 2 - 5 = 7 7 x 3 + 6 = 27 27 x 4 - 7 = 101 101 x 5 + 8 = 513 513 x 6 - 9 = 3069 Some steps which may be helpful to solve number series.
Step 1: Check difference Step 2: If step 1 does not work, then check difference of difference. If it also does not work, try to find is there any multiplication or division relationship between numbers? Step 3: If difference is sharply increasing or decreasing, then you can guess that it may be due to multiplication or division pattern of series.
Step 4: If there is more irregularity in difference, then it may be combination of above discuss steps. Step 5: If none of the steps works, then try to use elimination method, which may help you in eliminating 2 to 3 options.
