Subject: General Aptitude · Chapter: Time and Work · Exam: 2007 · Marks: · Difficulty:
A and B can do a piece of work in 12 days, B and C in 8 days and C and A in 6 days. How long would B take to do the same work alone?
(a)24 days
(b)32 days
(c)40 days
(d)48 days
Answer
Answer (as printed): D
Explanation
(A+B)'s 1 day's work $=\frac{1}{12}$; (B+C)'s 1 day's work $=\frac{1}{8}$; (A+C)'s 1 day's work $=\frac{1}{6}$. [(A+B)'s 1 day's work + (B+C)'s 1 day's work] $-$ (A+C)'s 1 day's work $=\frac{1}{12}+\frac{1}{8}-\frac{1}{6}=\frac{1}{24}$. $\Rightarrow 2$(B's 1 day's work)$=\frac{1}{24} \Rightarrow$ B's 1 day's work $=\frac{1}{48}$. Hence, B alone can do the work in 48 days.
Explanation as extracted from the printed page; notation may be imperfect.