Answer:
The value is 
Step-by-step explanation:
From the question we are told that
The mean is 
The standard deviation is 
The safest water level is between 7.2 and 7.8
Generally the probability that the selected pool has a pH level that is not considered safe is mathematically represented as

Here

Generally 
So
=>
From the z-table the probability of (Z < -1.5) and ( Z <1.5) are

and

So
So

=> 
3.6 * 10^(-3) is the scientific notation
Gross income : 785 per week
deductions are :
FICA : 42.25
income tax : 90.33
2% state tax : 0.02(785) = 15.70
1% city tax : 0.01(785) = 7.85
3% retirement : 0.03(785) = 23.55
total deductions are : 42.25+90.33+15.70+7.85+23.55 = 179.68
gross pay - deductions = net pay
785 - 179.68 = net pay
605.32 = net pay <====