Huh? Are you missing the something
The surface area of a cube is:
A=6s^2 (It is just the area of 6 sides (squares) all having an area of s^2)
A=7.2^3=373.248 ft^3
Answer:
The answer is below
Step-by-step explanation:
Let x represent the number of small hat purchased, y represent the number of medium hat purchased and z represent the number of large hat purchased.
Since a total of 47 hats where purchased, hence:
x + y + z = 47 (1)
Also, he spent a total of $302, hence:
5.5x + 6y + 7z = 302 (2)
He purchases three times as many medium hats as small hats, hence:
y = 3x
-x + 3y = 0 (3)
Represent equations 1, 2 and 3 in matrix form gives:
![\left[\begin{array}{ccc}1&1&1\\5.5&6&7\\-3&1&0\end{array}\right] \left[\begin{array}{c}x\\y\\z\end{array}\right] = \left[\begin{array}{c}47\\302\\0\end{array}\right] \\\\\\\\ \left[\begin{array}{c}x\\y\\z\end{array}\right] =\left[\begin{array}{ccc}1&1&1\\5.5&6&7\\-3&1&0\end{array}\right] ^{-1} \left[\begin{array}{c}47\\302\\0\end{array}\right] \\\\\\ \left[\begin{array}{c}x\\y\\z\end{array}\right] = \left[\begin{array}{c}6\\18\\23\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%261%261%5C%5C5.5%266%267%5C%5C-3%261%260%5Cend%7Barray%7D%5Cright%5D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7Dx%5C%5Cy%5C%5Cz%5Cend%7Barray%7D%5Cright%5D%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D47%5C%5C302%5C%5C0%5Cend%7Barray%7D%5Cright%5D%20%5C%5C%5C%5C%5C%5C%5C%5C%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7Dx%5C%5Cy%5C%5Cz%5Cend%7Barray%7D%5Cright%5D%20%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%261%261%5C%5C5.5%266%267%5C%5C-3%261%260%5Cend%7Barray%7D%5Cright%5D%20%5E%7B-1%7D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D47%5C%5C302%5C%5C0%5Cend%7Barray%7D%5Cright%5D%20%5C%5C%5C%5C%5C%5C%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7Dx%5C%5Cy%5C%5Cz%5Cend%7Barray%7D%5Cright%5D%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D6%5C%5C18%5C%5C23%5Cend%7Barray%7D%5Cright%5D)
Therefore he purchases 6 small hats, 18 medium hats and 23 large hats
Let:
x = cost of senior citizen ticket
y = cost of student ticket
4x + 5y = 102
7x + 5y = 126
4x + 5y = 102
4x = 102 - 5y
x = (102 - 5y)/4
x = 102/4 - 5y/4
7x + 5y = 126
7(102/4 - 5y/4) + 5y = 126
(714/4 - 35y/4) + 5y = 126
-35y/4 + 5y = 126 - 714/4
note:
-35y/4 = -8.75y
714/4 = 178.5
-8.75y + 5y = 126 - 178.5
-3.75y = -52.5
y = -52.5/-3.75
y = 14
x = 102/4 - 5y/4
x = 102/4 - 5(14)/4
x = 8
x = cost of senior citizen ticket = $8/ea
y = cost of student ticket = $14/ea