Question 490214
A can do a work in 36 days, B can do the work in 72 days and C can do the work in 78 days.
The three take turns in working, i.e. A works on the first day, B works on the second day, C on the third day and so on. 
Which day will they finish the work?
:
Let d = the no. of days for the three men to do the work
Let the completed job = 1
:
{{{((1/3)d)/36}}} + {{{((1/3)d)/72}}} + {{{((1/3)d)/78}}} = 1 
Multiply by 2808 to clear the denominators
78({{{1/3}}}d) + 39({{{1/3}}}d) + 36({{{1/3}}}d) = 2808
26d + 13d + 12d = 2808
51d = 2808
d = {{{2808/51}}}
d = 55.06, therefore completion will occur on the 56th day