JEE Main 2026: Preparation Tips & Study Plan | Previous 10 Year Questions
JEE Main 2026: 100 Days Study Plan | High Scoring Chapters and Topics | Preparation Tips
JEE Main 2025 Most Scoring Concept: January Session | April Session
Don't Miss: Best Public Engineering Colleges | Top 30 Most Repeated Questions & Topics
Hello aspirant,
Sorry for the wrong answer issued earlier. The answer will be 5 instead of 4.
The question is:
{2(n-1)*(n+1-1)}/2= 20
The answer is done as follows-
=> (n-1)*(n-1+1)= 20
=> n(n-1)= 20
=> n^2-n-20= 0
=> n^2-5n+4n-20= 0
=> (n^2-5n)*(4n-20)= 0
=> n(n-5)*4(n-5)= 0
=> (n+4)*(n-5)= 0
=> n+4= 0 OR n-5= 0
=> n=5 (Ans)
Hope, it helps you.
Download the JEE Main 2026 Preparation Tips PDF to boost your exam strategy. Get expert insights on managing study material, focusing on key topics and high-weightage chapters.
Answer Key | Eligibility | Application | Preparation Tips | Question Paper | Admit Card | Result | Accepting Colleges
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile