If mean of 1, 2, 3, --------- n is 6n/11, then n is
can u pls give a proper brief explaination pls ??
The sum of a series of integers (1,2,3.. n)is
n(n+1)/2
so the mean is the total/n, hence
n(n+1)/2n
=6n/11
solve for n
I got n=11
I am not understand your answer
To find the value of n in an arithmetic sequence when the mean of the first n terms is given, we can use the formula for the arithmetic mean.
The formula for the arithmetic mean of an arithmetic sequence is as follows:
Mean = (First Term + Last Term) / 2
In this case, we are given the mean as 6n/11. We need to find the value of n.
So, let's set up the equation:
6n/11 = (1 + n) / 2
To solve the equation, we can start by cross-multiplying:
12n = 11(1 + n)
Now, distribute 11 into the parentheses:
12n = 11 + 11n
Next, let's isolate the variable terms by subtracting 11n from both sides:
12n - 11n = 11
Combine like terms on the left side:
n = 11
Therefore, the value of n is 11.