Question

A and B together can complete a work in $4$ days. A alone can finish the work in $12$ days, In how many days B alone can finish the work?

• A. $5$
• B. $15$
• C. $6$
• D. $8$

Answer 1

Answer: (C)

$6$

$\left(\begin{array}{c}A+B\end{array}\right)$"s $1$ day work $=\frac{1}{4}$
A"s $1$ day work $=\frac{1}{12}$
B"s $1$ day work $=\left[\begin{array}{c}\left(\begin{array}{c}\frac{1}{4}\end{array}\right)-\left(\begin{array}{c}\frac{1}{12}\end{array}\right)\end{array}\right]=\frac{1}{6}$
So, B can complete the work in $6$ days