Subject: General Aptitude · Chapter: Time and Work · Exam: 2003 · Marks: · Difficulty:
A and B can together finish a work in 30 days. They worked together for 20 days and then B left. After another 20 days, A finished the remaining work. In how many days A alone can finish the job ?
(a)40
(b)50
(c)54
(d)60
Answer
Answer (as printed): D
Explanation
(A+B)'s 20 days' work $=\left(\frac{1}{30} \times 20\right)=\frac{2}{3}$. Remaining work $=\left(1-\frac{2}{3}\right)=\frac{1}{3}$. Now, $\frac{1}{3}$ work is done by A in 20 days. $\therefore$ Whole work will be done by A in $(20 \times 3) = 60$ days.
Explanation as extracted from the printed page; notation may be imperfect.