Question

The mean of 1,2,3,...,n is 6n/11, then what is the value of 'n'?

Answer 1

The answer is in the attachment

Answer 2

Given,

1,2,3,4, ---, n

Mean of the given series = 6n/11

To find,

The value of n.

Solution,

The value of n will be 11.

We can easily solve this problem by following the given steps.

By observing the given series, we find that the difference between the two terms is one. So, the given series is a series of natural numbers.

[ More to know: Mean = Sum of all the observations/number of observations.]

Now, we know that mean of n natural numbers is n(n+1)/2.

According to the question,

Mean of the terms = 6n/11

(n+1)/2 = 6n/11

Using the cross multiplication method,

11(n+1) = 12n

11n + 11 = 12n

11 = 12n - 11n ( Moving 11n from the left-hand side to the right-hand side will result in the change of the sign from plus to minus.)

n = 11

Hence, the value of n is 11.