SAT Mathematics Practice Test 2

The value of m when l is $73$ can be found by substituting the $73$ for l in $\mathit{l}=24+3.5\mathit{m}$ and then solving for $\mathit{m}$. The resulting equation is $73=24+3.5\mathit{m}$; subtracting 24 from each side gives $49=3.5\mathit{m}$. Then, dividing each side of $49=3.5\mathit{m}$ by $3.5$ gives $14=\mathit{m}$. Therefore, when $\mathit{l}$ is $73$, $\mathit{m}$ is 14.
Choice B is incorrect and may result from adding $24$ to $73$ , instead of subtracting $24$ from $73$, when solving $73=24+3.5\mathit{m}$. Choice C is incorrect because $73$ is the given value for $\mathit{l}$, not for $\mathit{m}$. Choice D is incorrect and may result from substituting $73$ for $\mathit{m}$, instead of for $\mathit{l}$, in the equation $\mathit{l}=24+3.5\mathit{m}$.