Step-by-step explanation:

So what I think is that you multiply 4 by 4 or add 4 four times.Then, you would multiply 16 with 12 because there are 12 boxes and each box is 16. After doing that, you will get 192. Hope it helps :)
Answer:
He would gain by choosing air travel if, and only if, he values his time at more than $5 per hour.
Step-by-step explanation:
The problem states that:
A bus ticket from Washington to St. Louis costs $100, while it takes 32 hours to arrive.
A plane ticket from Washington to St. Louis costs $250, while it takes 2 hours to arrive.
Other things constant, Andrew would gain by choosing air travel if, and only if, he values his time at more than
If Andrew choses to go by plane, he saves 32-2 = 30 hours at the expense of $250-$100 = $150.
So, dividing the extra cost by the number of hours saved:

He would gain by choosing air travel if, and only if, he values his time at more than $5 per hour.
Answer: a. 34
Step-by-step explanation:
An easy way to do this is by using the simplest equations you can:
x + y and x - y
(3, 5) is (x, y). all you have to do is plug those into your equations and get a result, so:
x + y = 8
(because 3 + 5 = 8)
x - y = -2
(because 3 - 5 = -2)
and those can serve as your system of equations.
you can check it by solving by substitution:
x - y = -2
x + y = 8
solve one of the equations for a single variable:
x = y - 2
plug it into the second equation:
(y - 2) + y = 8
y - 2 + y = 8
2y - 2 = 8
2y = 10
y = 5
then plug that result back into the equation:
x + y = 8
x + 5 = 8
x = 3