Subject: General Aptitude · Chapter: Time and Work · Exam: · Marks: · Difficulty:
A works twice as fast as B. If B can complete a work in 12 days independently, the number of days in which A and B can together finish the work is
(a)4 days
(b)6 days
(c)8 days
(d)18 days
Answer
Answer (as printed): A
Explanation
Ratio of rates of working of A and B = 2:1. So, ratio of times taken = 1:2. $\therefore$ A's 1 day's work $=\frac{1}{6}$; B's 1 day's work $=\frac{1}{12}$. (A+B)'s 1 day's work $=\left(\frac{1}{6}+\frac{1}{12}\right)=\frac{3}{12}=\frac{1}{4}$. So, A and B together can finish the work in 4 days.
Explanation as extracted from the printed page; notation may be imperfect.