Answer:
a. $45.54; b. $51.42; c. See below
Step-by-step explanation:
a. 193 min
         Service charge = $40.00
 1st 100 min @ 0.021 =      2.10
Next 93 min @0.037 = <u>    3.44
</u>
                         Total =  $45.54
b. 317 min
           Service charge = $40.00
   1st 100 min @ 0.021 =      2.10
 2nd 100 min @ 0.037 =     3.70
         117 min @ 0.048 =   <u>   5.62</u>
                           Total =   $51.42
c. Piecewise function
The charge is  
- $40.00 + 0.021t               if t ≤ 100
- $42.10 + 0.037(t - 100)    if 100 < t ≤ 200
- $45.80 + 0.048 (t - 200) if t > 200
which we can write like this:

 
        
             
        
        
        
I think it does equal x but not really fully sure
        
             
        
        
        
There are 144 square inches in a square foot.
<u><em>Explanation</em></u>
A common size for floor tiles is 1 square foot in area.
We know that, <u> 1 foot = 12 inches. </u>
So, 1 square foot = (1 foot × 1 foot)                                                                                 = (12 inches × 12 inches ) = 144 square inches. 
So, there are 144 square inches in a square foot.
 
        
             
        
        
        
C. 3.50 W
Hope this helps you out with your homework!