Chapter 13.3, Problem 43STP

To determine

The sum of the remaining four numbers.

Answer to Problem 43STP

The sum of the remaining four numbers is 9.

Explanation of Solution

Given:

The mean of the seven numbers is 0.

The sum of the three of the numbers is -9

Since, mean=0

The mean of the seven numbers are expressed as::

  $\frac{a+b+c+d+e+f+g}{7}=0\mathrm{..........}\left(1\right)$

The sum of the three numbers is -9. Hence:

  $a+b+c=-9\mathrm{..........}\left(2\right)$

Solving equation 1 and 2:

  $\begin{array}{l}\frac{-9+d+e+f+g}{7}=0\\ -9+d+e+f+g=0\\ d+e+f+g=9\end{array}$

Thus, the sum of the remaining four numbers is 9.