Question : P, Q, and R alone can complete a piece of work in 30 hours, 10 hours and 15 hours respectively. In how much time will they finish the work if they work together?
Option 1: 5 hours
Option 2: 4 hours
Option 3: 8 hours
Option 4: 10 hours
Correct Answer: 5 hours
Solution :
The rate at which P, Q, and R work is $\frac{1}{30}$, $\frac{1}{10}$, and $\frac{1}{15}$ of the work per hour, respectively.
When they work together, their combined rate is $ = \frac{1}{30} + \frac{1}{10} + \frac{1}{15} = \frac{1}{5}$ of the work per hour
$\therefore$ The time it takes for them to finish the work together is the reciprocal of their combined rate $= \frac{1}{\frac{1}{5}} = 5$ hours
Hence, the correct answer is 5 hours.
Related Questions
Know More about
Staff Selection Commission Multi Tasking ...
Answer Key | Cutoff | Selection Process | Preparation Tips | Eligibility | Application | Exam Pattern
Get Updates Brochure
Your Staff Selection Commission Multi Tasking Staff Exam brochure has been successfully mailed to your registered email id “”.
Upcoming Exams
Trending Articles around SSC MTS
