Quantitative Aptitude Ques 1455
Question: A can do $ \frac{7}{8} $ of work in 28 days, B can do $ \frac{5}{6} $ of the same work in 20 days. The number of days they will take to complete. If they do it together, is [SSG (CPO) 2014]
Options:
A) $ 15\frac{3}{7}days $
B) $ 17\frac{3}{5}days $
C) $ 14\frac{5}{7}days $
D) $ 13\frac{5}{7}days $
Show Answer
Answer:
Correct Answer: D
Solution:
- A can do $ \frac{7}{8} $ work in 28 days.
$ \therefore $ He alone can do the total work in $ 28\times \frac{8}{7} $ days = 32 days. Now, one day work of $ A=\frac{1}{32} $ B can do $ \frac{5}{6} $ work in 20 days He alone can do the total work in $ 20\times \frac{6}{5} $ days = 24 days Now, one day work of $ B=\frac{1}{24} $
$ \therefore $ One day work of A and 8 working together $ =\frac{1}{24}+\frac{1}{32}=\frac{4+3}{96}=\frac{7}{96} $
$ \therefore $ Number of days required by A and B working together $ =\frac{96}{7}=13\frac{5}{7}days $
BETA
