20 men can finish a work in 220 days, but at the end of 90 days, 20 additional men are employed. In how many more days will the work be completed?

65

Using Formula,

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

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

⇒ Here, 20 men worked for 90 days. now days left are 130 days and 20 more men are employed. 

⇒ Therefore, the more time it will take to complete the project will be ;

⇒ 20 x 130 = 40 x  \( {D}_{2} \)

⇒ \( {D}_{2} \) = 65 days more.