# CAT Quantitative Aptitude Questions | CAT Algebra - Progressions questions

###### CAT Questions | Algebra | Arithmetic Progressions - Common Difference
CAT Questions

The question is about common difference of an Arithmetic Progression. Sum of the first 'n' terms and next 'n' terms are given and we need to find out the common difference. With some simple but very powerful ideas, one can cut down on a lot of working when it comes to progressions. For example, anchoring a progression around its middle term can be very useful. CAT Exam tests the idea of progression often in the CAT Quantitative Aptitude section and this could also be tested in DI LR section of the CAT Exam as a part of a puzzle.

Question 3: Sum of first 25 terms in AP is 525, sum of the next 25 terms is 725, what is the common difference?

1. $$frac{8}{25}\\$ 2. $\frac{4}{25}\\$ 3. $\frac{6}{25}\\$ 4. $\frac{1}{25}\\$ ## Best CAT Online Coaching Try upto 40 hours for free Learn from the best! #### 2IIM : Best Online CAT Coaching. ## Best CAT Coaching in Chennai #### CAT Coaching in Chennai - CAT 2022Limited Seats Available - Register Now! ### Explanatory Answer ##### Method of solving this CAT Question from CAT Algebra - Progressions: How you would relate the first 25 terms and the next 25 terms? The sum of the first 25 terms, S25 = 525 The sum of the next 25 terms, K25 = sum of next 25 terms = 725 a26 = a1 + 25d a27 = a2 + 25d K25 = a26 + a27 + ...... + a50 Or K25 = a1 + 25d + a2 + 25d + ...... + a25 + 25d Or K25 = a1 + a2 + ...... + a25 + 25$25d)

Or K25 = S25 + 25(25d)
i.e., 725 = 525 + 25 * 25d
200 = 25 * 25d
8 = 25d
d = $$frac{8}{25}\\$ The question is "what is the common difference?" ##### Hence the answer is "$\frac{8}{25}\\$" Choice A is the correct answer. ###### Best CAT Online Coaching Try upto 40 hours for free Learn from the best! ###### Already have an Account? ###### CAT Coaching in ChennaiCAT 2024 Classroom Batches Starting Now! @Gopalapuram ###### Best CAT Coaching in Chennai Introductory offer of 5000/- Attend a Demo Class ###### Best Indore IPM & Rohtak IPM CoachingSignup and sample 9 full classes for free. Register now! ## CAT Online Preparation | CAT Algebra Videos On YouTube #### Other useful sources for Algebra Questions | Arithmetic Progressions Geometric Progressions Sample Questions ##### Where is 2IIM located? 2IIM Online CAT Coaching A Fermat Education Initiative, 58/16, Indira Gandhi Street, Kaveri Rangan Nagar, Saligramam, Chennai 600 093 ##### How to reach 2IIM? Phone:$91) 44 4505 8484
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