Answer:
The original salary of the guard was $640 per week before the increase.
Step-by-step explanation:
Let the original salary of the guard = $ m
Now, increase in the salary = 25%
or, increase in the salary = 25% of m
25% of m = [tex]\frac{25}{100} \times m = 0.25m[/tex]
So, the Increased salary = Original Salary + Increment
= $ m + $ 0.25 m
= $(1.25) m
Also, the increased salary = $ 800
⇒ $(1.25) m = $ 800
or, 1.25 m = 800 ⇒ m= 800/1.25
or, m = 640
Hence, the original salary of the guard = m = $640