## 6. If mean of first n natural number is l number is 5 9 then n= (a)5 (b)4 (c)9 (d)10​

Question

6. If mean of first n natural number is l number is 5

9

then n=

(a)5 (b)4 (c)9 (d)10​

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1 month 2021-08-14T08:31:01+00:00 2 Answers 0 views 0

9

Step-by-step explanation:

It is given that the mean of first n natural numbers is
5n/9

⇒n+1/2=5n/9

⇒9n+9=10n

⇒n=9

2. Step-by-step explanation:

c)9

It is given that the mean of first n natural numbers is

9

5n

.

Therefore,

n

1+2+3+…+n

=

9

5n

2

n+1= 9

5n

⇒9n+9=10n

⇒n=9