# IBPS Specialist Officers Exam: Quantitative Aptitude-Number Series-Concept & Sample Questions

Institute of Banking and Personnel Selection (IBPS) will conduct common written examination for recruitment of Specialist Officers. The IBPS SO Exam 2015 will be conducted in the month of February 2015.

Jan 6, 2016 12:32 IST

Institute of Banking and Personnel Selection (IBPS) will conduct common written examination for recruitment of Specialist Officers (SO). The IBPS SO Exam will be conducted in the last week of January 2016.

The banking team of jagranjosh.com has brought concept and sample questions for Number series (Quantitative Aptitude). The concept provided by us will help you to understand the topic. The sample questions offered by us are framed by keeping in view need of the question paper.

Type 1 To Find the Missing Term

Directions (Q. Nos. 1 to 2): Find the missing term in each oy the following number series.

Example 1 13, 18, 16, 21, 19, 24,?

Solution: Clearly, the given series follows the pattern +5, -2, +5, -2, …….

So,                                           Missing term = 24 – 2 = 22

Example 2 3333, 3233, 3143, 3063,?

Solution: Clearly, the given series follows the pattern -100, -90, -80, -70, ………

So,                                           Missing term = 2993

Triangular Pattern Series

In such a series, the difference between the consecutive terms of a series, again form a series. The difference between the consecutive terms of the new series so formed again forms a series. This pattern continues till we attain a constant difference between the consecutive terms of the series.

Example 3 4, 18, 48, 100, 180, 294,?

Solution:

So, the missing term = 34 + 6 = 40

Then, 40 + 114 = 154 and 294 + 154 = 448

Type 2 To Pick the Odd One

Directions (Q. Nos. 5 to 6): In each of the following number series, one of the given numbers is wrong. Find out the number.

Example 4 2, 7, 14, 23, 36, 47, 62

Solution: Clearly, the correct sequence is 22 - 2, 32 - 2, 42 - 2, 52 - 2, 62 - 2, 72 - 2, 82 - 2.

So, 36 is wrong and should be replaced by (62 -2) =34

Example 5 1, 27, 125, 343, 729, 1321

Solution: Clearly, the correct sequence is 13, 33, 53, 73, 93, 113

So, 1321 is wrong and should be replaced by 113 = 1331

Sample Questions with Solutions and Explanations