Question

A can do a piece of work in 7 days of 9 hours each where as B can do the same work in 6 days of 7 hours each. How long will they take to do the work together, working \(8\frac{2}{5}\) hours a day?

• A. 2 days
• B. 3 days
• C. \(3\frac{1}{7}\)
• D. \(4\frac{2}{5}\)

Answer 1

The Correct Option is B

Work done by A and B in 1 hr per day \(=\frac{1}{63}+\frac{1}{42}=\frac{5}{126}\)

Number of hours they are required to work \(=\frac{42}{5} \) hours

Number of days required \(=(\frac{\frac{1}{5}}{126})\) ÷ \((\frac{42}{5})\)

\(=\frac{126}{5}\) × \(\frac{5}{42}=3\) days

⇒ Ans - (B).The correct option is (B): 3 days