Quantitative Aptitude Ques 674
Question: A and B alone can complete a work in 9 and 18 days, respectively. They worked together, however 3 days before the completion of the work A left. In how many days was the work completed?
Options:
A) 13
B) 8
C) 6
D) 5
Show Answer
Answer:
Correct Answer: B
Solution:
- Let the work is completed by A and B together in x days.
$ \therefore $ $ \frac{x-3}{9}+\frac{x}{18}=1 $
$ \Rightarrow $ $ \frac{2x-6+x}{18}=1 $
$ \Rightarrow $ $ 3x=24 $
$ \Rightarrow $ $ x=8 $
Alternate Method
Here, $ x=9, $ $ y=18 $ and $ t=3 $
$ \therefore $ Total number of days taken by A and 8 $ =\frac{y(x+t)}{x+y}=\frac{18(9+3)}{9+18}=\frac{18\times 12}{27}=8days $
BETA
