The answer is c because it makes the most sense
For this case we have the following solution.
x = gallons of water to be added
For the 10% solution we have:
0.1 * 8 = 0.8
Then, for 5% we have:
(0.8 / x + 8) = 0.05
Rewriting:
(0.8 / x + 8) = (5/100)
Answer:
An equation can be used to find x, the humber of gallons of water he should add is:
(0.8 / x + 8) = (5/100)
Alright assuming they mean total surface area since they didn't say lateral the equation to follow would be S= Ph + 2B
Start with P:
P stands for perimeter, so add up all the edges on one face of the cube.

Then your equation becomes
S= 68×h + 2B
h=height and that's obviously 17
so, S= 68×17 +2B
Now to find B. This is pretty easy. All you need to do is take 17×17 because you're finding the area of the base. This equals 289.
Finally this leaves us with the equation
S= 68×17+2×289
From there on you just solve it out.
This would leave you with 1734.