Question

A is thrice as good a workman as B and takes 10 days less to do a piece of work than B takes. B can do the work in _______.

• A. $12$ days
• B. $15$ days
• C. $20$ days
• D. $30$ days

Answer 1

Answer: (B)

$15$ days

Given, Work Efficiency ratio of A:B is 3:1

Let B takes $xdays$ to do the work. So according to the question, A takes $x-10days$ to do the same work. Time ratio and efficiency ratio are inversely proportional. So equating the ratios,

$\frac{x-10}{x}=\frac{1}{3}$

$⟹x=15$

Therefore, B can finish the work alone in $15days$