Question 78
Efficiency of A is twice as that of B. If they work together, they can complete a job in 18 days. If A alone does the job, in how many days he will complete the job?
Solution
Let total work = 18 units
Let B's efficiency = $$x$$ units/day and A's efficiency = $$2x$$ units/day
According to ques, working together, they finish work in = $$(x+2x)\times18=18$$
=> $$3x=1$$
=> $$x=\frac{1}{3}$$
$$\therefore$$ Time taken by A alone to finish the work = $$\frac{18}{\frac{1}{3}}=54$$ days
=> Ans - (D)
