Question 397884
Four men working together can dig a ditch in 42 days.
Find the number of man-days to complete the job
4*42 = 168 man-days
:
They begin, but one man works only half-days.
 How long will it take to complete the job?
Let d = no. days to complete the job 
d(3 + .5) = 168
3.5d = 168
d = {{{168/3.5}}}
d = 48 days