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Solution


Q.

If the mean of the first n natural numbers is 15, then value of n is:
1 28  
2 29  
3 30  
4 31  

Ans.

(2)

We have, mean of first n natural numbers

= n(n+1)2n⇒15=(n+1)2⇒n+1=30⇒n=30-1=29∴n=29