arithmetic - mishra takes twice as much time as dinesh or thrice as much time as umesh to finish a piece of work working together they can finish the work in 2 days dinesh can do the work alone in - skillgun

Suppose Mishra, Dinesh and Umesh take x,x/2 and x/3 hours respectively to finish the work.
Then, (1/x+2/x+3/x) = 1/2
=> 6/x=1/2
=> x = 12.
So, Dinesh takes 6 hours to finish the work.