A water tank

Tom has a water tank that holds 5 gallons of water. Tom uses water from a full tank to fill six bottles, which hold 16 ounces, and a pitcher, which holds 1/2 a gallon. How many ounces of water are left in the water tank?

Correct answer:

x =  480 oz

Step-by-step explanation:

$$\begin{gathered} 1gal=128o_z \\ {V}_1=5\cdot 128=640\text{oz} \\ x=V_1-6\cdot 16-\frac{1}{2}\cdot 128=640-6\cdot 16-\frac{1}{2}\cdot 128=480\text{oz} \end{gathered}$$

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