Time And Work Ques 14
Question-
A can complete a job in 36 days. $B$ is twice as efficient as A. A started the work and was joined by $B$ after a few days. If the whole work was completed in 15 days, after how many days from the time A started working did B join with $A$ ?
(1) $4 \frac{1}{2}$ days
(2) 4 days
(3) $5 \frac{1}{2}$ days
(4) 5 days
(5) None of these
(United Bank of India PGDBF Manipal Exam,07.08.2016)
Show Answer
Correct Answer: (1)
Solution: (1)
A’s 1 day’s work $=\frac{1}{36}$
$\because B$ is twice as efficient as A.
$\therefore$ B’s 1 day’s work $=\frac{1}{18}$
Let $B$ join with $A$ after $x$ days.
$\therefore \frac{15}{36}+\frac{15-x}{18}=1$
$\Rightarrow \frac{15+30-2 x}{36}=1$
$\Rightarrow 45-2 x=36$
$\Rightarrow 2 x=45-36=9$
$\Rightarrow x=\frac{9}{2}=4 \frac{1}{2}$ days
BETA
