30 men can do a work in 40 days. When should 10 men leave the work so that the entire work is completed in 40 days after they leave the work?  Select:
A) 87 days B) 10 days C) 55 days D) 44 days E) 20 days
Total work to be done = 30 * 40= 
<gadget id="calculator">30 * 40</gadget>
<output>1_200</output>
1200   Let 10 men leave the work after 'P' days, so that the remaining work is completed in 40 days after they leave the work.   40P + (10 * 40)= 1200   40P = 800 =&gt; P = 20 days   Answer:20 days
<result>E</result>
30 men can do a work in 40 days. When should 10 men leave the work so that the entire work is completed in 40 days after they leave the work?