If the mean of first n natural numbers i...

If the mean of first `n` natural numbers is `(5n)/9` , then `n=` (a) 5 (b) 4 (c) 9 (d) 10

A

5

B

4

C

9

D

none of these

Verified by Experts

The correct Answer is:

C

It is given that
`(1+2+3+ ... +n)/(n)=(5n)/(9) rArr n=9`

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