Indian Institute of Foreign Trade 2008 Solved Paper

© examsiri.com

Question : 35 of 150

Marks: +1, -0

If ,

(n+2)C_{8}:(n-2)P_{4}=57:16

then

n=

20
22
15
None of the above

Solution:

(n+2)C+2(n-2)P_{4}=57:16

8!∗(n−6)!

(n−2)!

(n-6)!

57

⇒\;\;=16

(n+2)(n+1)(n)(n−1)57

⇒8!=16

⇒(n+2)(n+1)(n)(n−1)=57∗2520

⇒(n+2)(n+1)(n)(n−1)=21∗20∗19∗18

Therefore, n = 19.

© examsiri.com

Go to Question:

Prev Question

Next Question