me thank yu tri tu sae "job require 7*40 man-daes" . . . =280 man-daes . . . then yu wanna no how long it take if...after 2 daes, 5% av werkers quit . . . start=40 werkers, so in 2 daes em du 80 man-daes . . . yet tu du=280-80=200 man-daes . . . with 38 werkers . . . part 2: 200/38=5.263157895 daes . . . time=2+5.263=7.263 daes