Answer:
John work as a security guard job <u>27 hours</u> and as a landscaper <u>33 hours</u>.
Step-by-step explanation:
Given:
John works two jobs.
As a security guard he earns $8.50 per hour and as a landscaper he earns $14 per hour.
One week John worked a total of 60 hours and earned $691.50.
Now, to find hours he work at each job.
Let the job of security guard be
hours.
And the job of landscaper be
hours.
So, the total hours John worked in a week:
![x+y=60.](https://tex.z-dn.net/?f=x%2By%3D60.)
⇒
............( 1 )
<em>Now, the money earned by John in a week:</em>
![8.50x+14y=691.50](https://tex.z-dn.net/?f=8.50x%2B14y%3D691.50)
<em>Putting the equation ( 1 ) in the place of
:</em>
⇒ ![8.50x+14(60-x)=691.50](https://tex.z-dn.net/?f=8.50x%2B14%2860-x%29%3D691.50)
⇒ ![8.50x+840-14x=691.50](https://tex.z-dn.net/?f=8.50x%2B840-14x%3D691.50)
<em>Moving variables on one side and the other we get:</em>
⇒ ![840-691.50=14 x-8.50x](https://tex.z-dn.net/?f=840-691.50%3D14%20x-8.50x)
⇒![148.50=5.50x](https://tex.z-dn.net/?f=148.50%3D5.50x)
<em>Dividing both sides by 5.50 we get:</em>
⇒ ![27=x](https://tex.z-dn.net/?f=27%3Dx)
<u>As a security guard job he worked 27 hours</u><u>.</u>
Putting the value of in
equation ( 1 ) we get:
![y=60-27](https://tex.z-dn.net/?f=y%3D60-27)
⇒ ![y=33.](https://tex.z-dn.net/?f=y%3D33.)
<u>As a landscaper he worked 33 hours</u>.
Therefore, John work as a security guard job 27 hours and as a landscaper 33 hours.