Answer:
Step-by-step explanation:
Given that a solution containing 12% alcohol is to be mixed with a solution containing 4% alcohol to make 20 gallons of solution containing 9% alcohol.
Let x gallons of 12% alcohol be mixed with y gallons of 4% alcohol.
Total gallons
Alcohol content in the total mixture 
b) Two equations are
c) This is of the form Ax = B
where A =![\left[\begin{array}{ccc}1&1\\12&4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%261%5C%5C12%264%5Cend%7Barray%7D%5Cright%5D)
Inverse is ![\frac{1}{4-12} \left[\begin{array}{ccc}4&-1\\-12&12\end{array}\right]\\=\frac{-1}{8} \left[\begin{array}{ccc}4&-1\\-12&12\end{array}\right]\\](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B4-12%7D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D4%26-1%5C%5C-12%2612%5Cend%7Barray%7D%5Cright%5D%5C%5C%3D%5Cfrac%7B-1%7D%7B8%7D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D4%26-1%5C%5C-12%2612%5Cend%7Barray%7D%5Cright%5D%5C%5C)
Solution set is A inverse *B
= 
28 divided by 4 = 7
so do 7 * 5 which is 35 so they make 35 cookies in 5 seconds
Answer:
it is A the first one welcome pls mark as brainliest hope this helps
Step-by-step explanation:
To answer this, you will write and equation in terms of the number of adult tickets sold and then solve for a, the number of adult tickets.
$5a + $3.50s = $2517.50
$5a + $3.50(a + 100) = $2517.50
5a + 3.50a + 350 = 2517.50
8.50a -350 -350
<u>8.5a</u> = <u>2167.50</u>
8.5 8.5
a = 255
The number of adult tickets sold was 255, and the number of student tickets sold was 355 (255 +100).
