Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Open MARKS Web Download App
Search any question & find its solution
Question: Answered & Verified by Expert
If n+2C8:n-2P4=57:16, then the value of n2 is
MathematicsPermutation CombinationJEE Main
Solution:
1610 Upvotes Verified Answer
The correct answer is: 9.5
n+2!8!n-6!×n-6!n-2!=5716
⇒n+2n+1nn-1=5716×8!
⇒n-1nn+1n+2=57×7×6×5×4×3
⇒n-1nn+1n+2=18×19×20×21
⇒n=19
⇒n2=9.5

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.

Use on iOS or Desktop Download from Google Play