SAT Mathematics Practice Test 6

The equation $12\mathit{d}+350=1,010$ can be used to determine d, the number of dollars charged per month. Subtracting 350 from both sides of this equation yields $12\mathit{d}=660$,and then dividing both sides of the equation by 12 yields $\mathit{d}=55$.
Choice A is incorrect. If d were equal to 25, the first 12 months would cost $350+\left(12\right)\left(25\right)=650$ dollars, not $\mathrm{\$}1,010$.Choice B is incorrect. If d were equal to 35, the first 12 months would cost $350+\left(12\right)\left(35\right)=770$ dollars, not $\mathrm{\$}1,010$. Choice C is incorrect. If d were equal to 45, the first 12 months would cost 350 + (12)(45) =890 dollars, not $\mathrm{\$}1,010$ dollars.