four men working together can create a trench in 42 days. they begin the job but one man works only half days. How long will it take to complete the trench?

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