Time And Work Ques 20
Question-
A can complete a task in 15 days. B is $50 \%$ more efficient than A. Both A and B started working together on the task and after a few days $B$ left the task and A finished the remaining one-third of the given work. For how many days $A$ and $B$ worked together?
(1) 3
(2) 5
(3) 4
(4) 6
(5) 2
(IBPS RRBs Officers CWE (Prelim Exam) 09.09.2017) IInd Sitting)
Show Answer
Correct Answer: (3)
Solution: (3)
A completes 1 work in 15 days. $B$ is $50 \%$ more efficient than $A$.
$\therefore$ Time taken by $B=\frac{100}{150} \times 15$ $=10$ days
A and B together completed $\frac{2}{3}$ of work.
$(A+B)$ ’s 1 day’s work $=\frac{1}{15}+\frac{1}{10}=\frac{2+3}{30}=\frac{5}{30}=\frac{1}{6}$
$\therefore$ Time taken by $A$ and $B$ in do-
ing $\frac{2}{3} rd$ work $=\frac{2}{3} \times 6$ $=4$ days
$\therefore$ A and B worked together for 4 days.
BETA
