d = 16 - x 30 The equation shown gives the estimated amount of diesel d

Choice B is correct. It’s given that the equation $d=16-\frac{x}{30}$ gives the estimated amount of diesel $d$, in gallons, that remains in the gas tank of the truck after being driven $x$ miles. Substituting $300$ for $x$ in the given equation yields $d=16-\frac{300}{30}$, which is equivalent to $d=16-10$, or $d=6$. Therefore, the estimated amount of diesel that remains in the gas tank of the truck when $x=300$ is $6$ gallons.

Choice A is incorrect. This is the estimated amount of diesel, in gallons, that will remain in the gas tank of the truck when $x=480$, not when $x=300$.

Choice C is incorrect. This is the estimated amount of diesel, in gallons, that will remain in the gas tank of the truck when $x=60$, not when $x=300$.

Choice D is incorrect. This is the estimated amount of diesel, in gallons, that will remain in the gas tank of the truck when $x=0$, not when $x=300$.