Answer:
Kirk is <u>28</u> years old, Brian is <u>36</u> years old, Matt is <u>18</u> years old, and the manager is <u>24</u> years old.
Step-by-step explanation:
Let
be Kirk's age.
Let
be Brian's age.
Let
be Matt's age.
Let
be the boss/manager's age.
From the information given, we can set up 4 equations:
![k+b+m+m_{1}=106](https://tex.z-dn.net/?f=k%2Bb%2Bm%2Bm_%7B1%7D%3D106)
![k=2(m_{1}-10)](https://tex.z-dn.net/?f=k%3D2%28m_%7B1%7D-10%29)
![b=2m_{1}-12](https://tex.z-dn.net/?f=b%3D2m_%7B1%7D-12)
![m=\frac{1}{2}m_{1}+6](https://tex.z-dn.net/?f=m%3D%5Cfrac%7B1%7D%7B2%7Dm_%7B1%7D%2B6)
Rewrite the first equation, substituting
,
, and
in terms of
to get:
![2(m_{1}-10)+(2m_{1}-12)+(\frac{1}{2}m_{1}+6)+m_{1}=106](https://tex.z-dn.net/?f=2%28m_%7B1%7D-10%29%2B%282m_%7B1%7D-12%29%2B%28%5Cfrac%7B1%7D%7B2%7Dm_%7B1%7D%2B6%29%2Bm_%7B1%7D%3D106)
Open up the parentheses using the distributive property (which is
) and combine like terms to get:
![5.5m_{1}-26=106](https://tex.z-dn.net/?f=5.5m_%7B1%7D-26%3D106)
Add 26 to both sides to reach:
![5.5m_{1}=132](https://tex.z-dn.net/?f=5.5m_%7B1%7D%3D132)
Thus,
. Substitute
for
in the second, third, and fourth original equations to find that
,
, and
. Therefore, Kirk is <u>28</u> years old, Brian is <u>36</u> years old, Matt is <u>18</u> years old, and the manager is <u>24</u> years old. To check, you can add up all of the ages to get 106.
Hope this helps :)