Answer: a) 1977060966, b) 146581344.
Step-by-step explanation:
Since we have given that 
There are 10 numbers,
There are 26 lower case letters,
There are 26 upper case letters,
Since the first 3 characters have to be digits and next 6 can be upper or lower.
So, a) repetitions are allowed:

b) repetitions are not allowed:

Hence, a) 1977060966, b) 146581344.
 
        
             
        
        
        
Answer:19800
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:

Step-by-step explanation:
Hello!
A line that is perpendicular to another has an opposite-reciprocal slope.
Meaning:
- Flip the sign (+/-)
- Flip the fraction
The slope perpendicular to 3/5 would be -5/3.
We can solve for the y-intercept by plugging in the x and y values given from the coordinate into the equation with out new slope.
<h3 /><h3>Solve for B</h3>
The y-intercept of the new line is 20.
The equation is 
 
        
             
        
        
        
How long would it take $120/hr to add up to $1000?
Divide $1000 by $120/hr:  
 $1000
----------- = 8 1/3 hours, or 8 hours 20 minutes.
$120/hr