<span>cube has six identical walls
96ft</span>²<span> : 6 = 6 ft</span>²<span> - </span>one wall surface
<span>pattern on the surface of the cube
</span>A = a²
a - <span>the edge of the cube
A = a</span>² ⇔ a=√A
a = √(16ft)² = 4ft
V = volume
V = a³
V = (4ft)³ = 64 ft³
112-88 = 24
they save $24 per month
so 650/24 = 27.083
so it will pay for itself in 27.083 months, round up to 28 months
If you assign variables to the problem, it can make things a lot simpler. Lets say chairs are x and tables are y. Therefore you have:
2x+6y=40
5x+3y=25
Now you can isolate the variable of one equation and put it into another (it doesn't matter which. I'm going to manipulate the top equation to plug into the bottom one).
2x=40-6y
x=20-3y
Now I plug into bottom equatioin:
5(20-3y) + 3y=25
100-15y+3y=25
100-12y=25
-12y=-75
y=$6.25
Now you can plug in y in either equation to get x.
2x+6(6.25)=40
37.5+2x=40
2x=2.5
x=1.25
So it costs $6.25 for each table and $1.25 for each chair. If you think about it, it would make sense for the table to cost more for the chair.
