Question

The mean monthly salary of 10 members of a group is Rs.1,445, one more member whose monthly salary is Rs.1,500 has joined the group. Find the mean monthly salary of 11 members of the group.

Answer 1

Here, n = 10, `bar"X"` = 1445.
So  `bar"X" = (1)/"n"(sumx_i)`
⇒ `"n"bar"X" = sumx_i`
⇒ 10 x 1445 = `sumx_i`
⇒ `sumx_i` = 14450.
So, total monthly salary of 10 persons is of ₹14450.
Monthly salary of one more person who joined the group is ₹1,500.
∴ Total monthly salary of 11 persons
= ₹14,450 + Rs. 1,500
= ₹15,950
So, average monthly salary of 11 persons
= `"Total monthly salary"/(11)`
= `(15950)/(11)`
= ₹1,450.