Question : To do a certain work, B would take time thrice as long as A and C together and C twice as long as A and B together. The three men together complete the work in 10 days. The time taken by A to complete the work separately is:
Option 1: 22 days
Option 2: 24 days
Option 3: 30 days
Option 4: 20 days
Correct Answer: 24 days
Solution : If B does the work in 3$x$ days, (A + C) will do the same work in $x$ days. If C does that work in 2$y$ days. (A + B) will do it in $y$ days. According to the question, $\frac{1}{x}+\frac{1}{3x}=\frac{1}{10}$ ⇒ $\frac{4}{3x}=\frac{1}{10}$ ⇒ $3x=40$ ⇒ $x=\frac{40}{3}$ So, B takes $3×\frac{40}{3}$ = 40 days Again, $\frac{1}{y}+\frac{1}{2y}=\frac{1}{10}$ ⇒ $\frac{3}{2y}=\frac{1}{10}$ ⇒ $y=15$ So, C takes $2×15$ = 30 days (A + B + C)'s 1 day work = $\frac{1}{10}$ ⇒ $\frac{1}{A}+\frac{1}{40}+\frac{1}{30}=\frac{1}{10}$ ⇒ $\frac{1}{A}=\frac{1}{10}-\frac{1}{40}-\frac{1}{30}$ ⇒ $\frac{1}{A}=\frac{12-3-4}{120} = \frac{1}{24}$ $\therefore$ A alone will complete work in 24 days. Hence, the correct answer is 24 days.
Result | Eligibility | Application | Selection Process | Cutoff | Admit Card | Preparation Tips
Question : A is twice as efficient as B and C is thrice as efficient as B. Working together, they can finish a certain work in 5 days. A and C worked together for 5 days. B alone would complete the remaining work in ____.
Question : A, B and C together can complete a work in 20 days. A and B together can complete the same work in 30 days. Then, C alone can complete the same work in how many days?
Question : To do a certain task X would take 3 times as long as Y and Z together, and Z would take 4 times as long as Y and X together. Three of them together can complete the task in 10 days. How much time is taken by X and Z to complete the task?
Question : A and B together can complete a piece of work in 18 days, B and C in 24 days, and A and C in 36 days. In how many days, will all of them together complete the work?
Question : A is twice as good a workman as B and B is twice as good a workman as C. If A and B can together finish a piece of work in 4 days, then C can do it by himself in:
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile