Question

# The mean monthly salary of $10$ members of a group is$Rs.1445$, one more member whose monthly salary is $Rs.1500$ has joined the group. Find the monthly salary of $11$ members of the group.

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Hint:Try to write down the formula of mean and figure out the knowns and unknowns in the equation. Make two equations, one with $10$ members and another one with $11$ members with the formula of average.Then finally find the mean of $11$ members of the group.

Before moving forward, let us try to understand the question properly first. The mean or average salary of $10$ members is given to be $Rs.1445$. Then another member is added with a monthly salary of $Rs.1500$. Now we have to find the new mean monthly salary of $11$ members of the group.
$\Rightarrow Mean = \dfrac{{Sum}}{{Number}}\dfrac{{of}}{{of}}\dfrac{{Observations}}{{Observations}}$
So, given information is that mean monthly salary of $10$ members of a group is $Rs.1445$, let’s try to put these values in the above equation
$\Rightarrow 1445 = \dfrac{{Sum}}{{10}}$ $\Rightarrow$ The total salary of $10$ members $= 1445 \times 10 = Rs.14450$
So now we got the total monthly salary of $10$ members and we already have a monthly salary of ${11^{th}}$ the member.
Therefore, the total salary of $11$ members of the group $= 14450 + 1500 = Rs.15950$
$\Rightarrow Mean = \dfrac{{15950}}{{11}} = Rs.1450$
Hence, the monthly salary for $11$ members of the group is $Rs.1450$