2 votes 2 votes how to solve such questions? Quantitative Aptitude made-easy-test-series general-aptitude system-of-equations + – charul asked Jan 5, 2018 • retagged Mar 5, 2019 by Aditi Singh charul 584 views answer comment Share Follow See all 6 Comments See all 6 6 Comments reply Pawan Kumar 2 commented Jan 5, 2018 reply Follow Share is ans 15? 0 votes 0 votes akshat sharma commented Jan 5, 2018 i edited by akshat sharma Jan 5, 2018 reply Follow Share 10 will be the answer when u r taking x^2 as common inside it will be 1+x^2+x^4+x^6.... now it simple GP question using simple formula$\binom{N+r-1}{r}$*x^2r which is $\binom{5}{2}$ 0 votes 0 votes sumit goyal 1 commented Jan 5, 2018 i reshown by sumit goyal 1 Jan 5, 2018 reply Follow Share akshat sharma link for formula plZ 1 votes 1 votes akshat sharma commented Jan 5, 2018 reply Follow Share sorry bro for late reply see this formula is commonly used in generating function topic and chocolate problem type question in combinotrics right now i dont have any link u can refer those topic (this is just inverse of (1-x)^n 0 votes 0 votes akshat sharma commented Jan 5, 2018 reply Follow Share here N=4,r=2 0 votes 0 votes Ajay Jadhav commented Jan 6, 2018 reply Follow Share Pull out first x^2 ,so it becomes 1+x^2+..... The outside x^2 becomes x^8 because of power 4,subtract this from x^12,... So we need to find coefficient of x^4 here Since this series is has even numbers ,it clearly says it has x of the form x^2r. ,And we are finding x^4 and thus r=2 Here n= 4,r=2 hence ,(4+2-1,2)=10 0 votes 0 votes Please log in or register to add a comment.
1 votes 1 votes For those who have dikkat in generating function can see it here (download image and and then change its position ) open it in paint for clear view sumit goyal 1 answered Jan 6, 2018 • edited Jan 6, 2018 by sumit goyal 1 sumit goyal 1 comment Share Follow See 1 comment See all 1 1 comment reply sumit goyal 1 commented Jan 6, 2018 reply Follow Share download it and zoom 1 votes 1 votes Please log in or register to add a comment.