If 25\% of a number is subtracted from a second number, the second number reduces to its five-sixths. What is the ratio of the first number to the second number?
(a)1: 3
(b)2: 3
(c)3: 2
(d)Data inadequate
Answer
Answer (as printed): B
Explanation
Let the numbers be $x$ and $y$. Then, $\quad y-25 \%$ of $x=$ $\frac{5}{6} y \Leftrightarrow y-\frac{5}{6} y=\frac{25}{100} x \Leftrightarrow \frac{y}{6}=\frac{x}{4} \Leftrightarrow \frac{x}{y}=\frac{4}{6}=\frac{2}{3}$.
Explanation as extracted from the printed page; notation may be imperfect.