Answer:
21 mails
Step-by-step explanation:
Let there are x no of texts and y no of emails.
Condition 1,
x+y = 20 ...(1)
Condition,
x=2y-1 ...(2)
Put the value of x from equation (2) in (1). So,
(2y-1)+y = 20
Taking like terms together,
2y-y=20+1
y=21
So, Devin sent 21 mails,.
The total cost without tax would be $261, sales tax would be $15.66, if we add them together the answer would be $276.66
Answer:

Step-by-step explanation:
A = the area of the region outside the semicircle but inside the rectangle
w = the width of the rectangle or diameter of the semicircle
Since "A" is determined by "w", therefore, "A" is a function of "w" = A(w).
A(w) = (area of rectangle) - (area of semicircle)

Where,
lenght of rectangle (l) = w + 5
width of rectangle (w) = w
r = ½*w = 
Plug in the values:


Simplify





C? either B or C i believe. Hope this helps