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:

⇒
............( 1 )
<em>Now, the money earned by John in a week:</em>

<em>Putting the equation ( 1 ) in the place of
:</em>
⇒ 
⇒ 
<em>Moving variables on one side and the other we get:</em>
⇒ 
⇒
<em>Dividing both sides by 5.50 we get:</em>
⇒ 
<u>As a security guard job he worked 27 hours</u><u>.</u>
Putting the value of in
equation ( 1 ) we get:

⇒ 
<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.