If $10$ persons can do a job in $20$ days, then $20$ persons with twice the efficiency can do the same job in:
Practice this question from Chapter Mock 7: Time and Work, Pipe and Cistern, with options and an explanation.
Question
If $10$ persons can do a job in $20$ days, then $20$ persons with twice the efficiency can do the same job in:
Option A — Correct answer
5 days
Correct choice.
Option B
8 days
Option C
10 days
Option D
20 days
Explanation
The workforce effect is multiplied by $20\times2=40$ compared with the original $10$. So the job is done in $20\times\frac{10}{40}=5$ days.