Answer:
The correct option is 3. Capacity of smallest tank is 15-gallons.
Step-by-step explanation:
The graph shows the relationship between capacity of tank and combined length of fish it can hold.
The line passing through (0,1) and (1,2).
Slope of the line is
![m=\frac{y_2-y_1}{x_2-x_1}=\frac{2-1}{1-0}=1](https://tex.z-dn.net/?f=m%3D%5Cfrac%7By_2-y_1%7D%7Bx_2-x_1%7D%3D%5Cfrac%7B2-1%7D%7B1-0%7D%3D1)
Slope intercept form of a line is
![y=mx+b](https://tex.z-dn.net/?f=y%3Dmx%2Bb)
Where, m is slope and b is y-intercept.
The slope of the line is 1 and the y-intercept is 1, therefore the equation of line is
..... (1)
If we want four 2-inch platys, three 1-inch guppies and a 3-inch loach, then the combined length of fish is
![4\times 2+3\times 1+1\times 3=8+3+3=14](https://tex.z-dn.net/?f=4%5Ctimes%202%2B3%5Ctimes%201%2B1%5Ctimes%203%3D8%2B3%2B3%3D14)
Therefore the combined length of fish is 14.
Put x=14 in equation 1.
Therefore, the capacity of smallest tank is 15-gallons and option 3 is correct.