Because the relationship is linear, find the rate of change first. From $t=1$ to $t=3$, the number of bacteria increases from $120$ to $200$, which is an increase of $80$ over $2$ hours. So the slope is $\frac{80}{2}=40$. This means the equation has the form $N=40t+b$. Substitute the point $(1,120)$: $120=40(1)+b$. So $120=40+b$, and $b=80$. Therefore, the equation is $N=40t+80$.

First find the slope of the line using the two points:

So the equation has the form $y=3x+b$. Substitute one of the given points, such as $(2,14)$:

Therefore, $b=8$. The equation is $y=3x+8$, which is choice A.

First find the slope of the line using the two points:

From $x=2$ to $x=6$, the change in $x$ is $4$. Since the slope is $-\frac{3}{2}$, the change in $y$ is

Starting from the point $(2,14)$, subtract $6$ from the $y$-value:

So when $x=6$, the $y$-value is $8$.

To write an equation for $W$ in terms of $t$, first find the constant rate of change from the table. From 3 to 7 minutes, time increases by 4 minutes and water increases from 58 to 86 gallons, which is 28 gallons. So the rate is $\frac{28}{4}=7$ gallons per minute.

That means the equation has the form $W=7t+b$, where $b$ is the initial amount of water.

Use any point from the table, such as $(3,58)$:

So the equation is

This matches choice A.

First find the median. Since there are 6 values, the median is the average of the 3rd and 4th values in order: $\frac{30+30}{2}=30$. Next find the mean: $\frac{20+25+30+30+35+70}{6}=\frac{210}{6}=35$. Since $35>30$, the mean is greater than the median, so choice A must be true.