Subject: General Aptitude · Chapter: Problems on Numbers · Exam: · Marks: · Difficulty:
A student was asked to divide the half of a certain number by 6 and the other half by 4 and then to add the two quantities so obtained. Instead of doing so the student divided the number by 5 and the result fell short by 4. The given number was (P.C.S., 2009)
(a)240
(b)288
(c)384
(d)480
Answer
Answer (as printed):
Explanation
Let the number be $x$. Then, $\left[\frac{(x/2)}{6}+\frac{(x/2)}{4}\right]-\frac{x}{5}=4 \Leftrightarrow \frac{x}{12}+\frac{x}{8}-\frac{x}{5}=4 \Leftrightarrow \frac{10x+15x-24x}{120}=4 \Leftrightarrow x=4\times120=480$.
Explanation as extracted from the printed page; notation may be imperfect.