Because the tank is cylindrical, its cross-sectional area is constant, so the volume of water is proportional to the height of the water level. If 2 feet of water corresponds to 180 gallons, then 1 foot corresponds to $\frac{180}{2}=90$ gallons. A water level of 5 feet therefore corresponds to $5\times 90=450$ gallons. So the correct answer is $450$.

First find the unit rate in gallons per minute: $\frac{18}{12}=1.5$ gallons per minute. Then multiply by 35 minutes: $1.5\times 35=52.5$. Therefore, the tank will dispense $52.5$ gallons in 35 minutes.

The ratio of concentrate to water must be $3:17$. Since 24 ounces of concentrate are already in the container, set up a proportion: $\frac{3}{17}=\frac{24}{w}$, where $w$ is the number of ounces of water. Cross-multiply: $3w=17\cdot 24=408$. Then divide by 3: $w=\frac{408}{3}=136$. So 136 ounces of water should be added.

In a proportional relationship, the ratio between the variables is constant. The point $(120,4)$ means 120 miles are driven using 4 gallons of gasoline. To find miles per gallon, divide miles by gallons: $\frac{120}{4}=30$. So the car travels 30 miles for each gallon of gasoline.

Let $p$ be the number of pounds of peanuts and $r$ be the number of pounds of raisins. The total weight gives the equation $p+r=30$. The total cost gives the equation $4p+7r=156$. Substitute $p=30-r$ into the cost equation: $4(30-r)+7r=156$. Then $120-4r+7r=156$, so $120+3r=156$. Subtract 120 from both sides: $3r=36$. Divide by 3 to get $r=12$. Therefore, 12 pounds of raisins were used.