20 men can finish a work in 30 days. They started working, but 4 men left the work after 10 days. In how many days would the work be completed?

35

Formula to be used here

⇒\( {M }_{ 1} \) x \( {D }_{ 1} \) = \( {M }_{ 2} \) x \( {D }_{ 2} \)

where, M = no. of men, D = no. of days,

⇒ Total work days = 20 x 30 = 600 man-days.

⇒ Total work done in 10 days = 20 x 10 = 200 man-days

⇒ Total work remaining = 600 - 200 = 400 man-days

⇒ Total time needed to complete the remaining work = 400 + 16 = 25

⇒ Total time needed to complete the whole work = 25 + 10 = 35 days

Therefore, The work would be completed in 35 days.