P can lay railway track between two stations in 16 days. Q can do the same job in 12 days. With the help of R, they completes the job in 4 days. How much days does it take for R alone to complete the work?
Choose the most appropriate option
A) 9(3/5) days B) 9(1/5) days C) 9(2/5) days D) 10 days E) 10(1/5) days
Explanation :   9(3/5) daysmount of work P can do in 1 day = 1/16   9(3/5) daysmount of work Q can do in 1 day = 1/12   9(3/5) daysmount of work P, Q and R can together do in 1 day = 1/4   9(3/5) daysmount of work R can do in 1 day = 1/4 - (1/16 + 1/12) = 3/16 – 1/12 = 5/48   =&gt; Hence R can do the job on 48/5 days = 9 (3/5) days   9(3/5) daysnswer : Option 9(3/5) days
<result>A</result>
P can lay railway track between two stations in 16 days. Q can do the same job in 12 days. With the help of R, they completes the job in 4 days. How much days does it take for R alone to complete the work?