Question 1028224
Here the job takes 40*40 = 1600 man-days.
After the 10th day, 1/4 of the job was done.  3/4 of the job to go...that would be 1200 man-days.
Five men leaving means there are 35 to finish...
The number of days to finish is
1200/35 = 34 2/7 days
And even if you add the original 10 days, you don't get one of the choices.
Please repost with the correct problem.