Answer:
Company B.
Step-by-step explanation:
On the graph, when x is 1, y is 50. That means it is $50 for one window. On the chart, when there is 1 window, the cost is $55. So, company B is more expensive!
The ratio of the volumes is equal to the scale factor cubed.
![\frac{V_1}{V_2}=k^3 \\ \\ \frac{320 \ cm^3}{1080 \ cm^3}=k^3 \\ \frac{8}{27}=k^3 \\ k=\sqrt[3]{\frac{8}{27}} \\ \boxed{k=\frac{2}{3}} \Leftarrow \hbox{answer B}](https://tex.z-dn.net/?f=%5Cfrac%7BV_1%7D%7BV_2%7D%3Dk%5E3%20%5C%5C%20%5C%5C%0A%5Cfrac%7B320%20%5C%20cm%5E3%7D%7B1080%20%5C%20cm%5E3%7D%3Dk%5E3%20%5C%5C%0A%5Cfrac%7B8%7D%7B27%7D%3Dk%5E3%20%5C%5C%0Ak%3D%5Csqrt%5B3%5D%7B%5Cfrac%7B8%7D%7B27%7D%7D%20%5C%5C%0A%5Cboxed%7Bk%3D%5Cfrac%7B2%7D%7B3%7D%7D%20%5CLeftarrow%20%5Chbox%7Banswer%20B%7D)
In this big ol' word problem, this is just an instance of basic multiplication/division.
If it takes it 1 hour for 3 meters...
12 ÷ 3 = 4.
It would take 4 hours for the water level to change to 12 meters.
The answer should be f(x)=20(2.5)^x
How?
the graph crosses the f(x) axis at 20 but that's common in all 4 equations. However, when x=1, f(x)=50. We have to know try all the equations by substituting these values in ( both sides are equal).
f(x)=20(2.5)^x
substitute f(x)=50, x=1
50=20(2.5)^1
50=20*2.5
50=50
