Answer:
48 days
Step-by-step explanation:
Four men working together can create a trench 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 trench
d(3 + 0.5) = 168
d(3.5)=168
3.5d = 168
d = 168/3.5
d = 48 days
