Question

$A$ can do a piece of work in $24$ days. If $B$ is $60\%$ more efficient than $A$, then the number of days required by $B$ to do the twice as large as the $A^{\prime }s$ work is -

• A. $36$
• B. $30$
• C. $15$
• D. $24$

Answer 1

Answer: (B)

A can do a work say $w$ in $24$ days

$A\to \frac{w}{24}$ (work done by A in one day)

$B$ is $60$% more efficient

$B\to 1.6\times \frac{w}{24}$ (work done by B in one day)

Now B has to do work $2w$

For one day B can do $B\to 1.6\times \frac{w}{24}$

Say B takes $x$ days to complete $2w$ amount of work.

$1.6\times \frac{w}{24}\times x=2w$

$x=\frac{48}{1.6}=30$