30 men can do a work in 40 days. When should 20 men leave the work so that the entire work is completed in 40 days after they leave the work? Choose one: A) 12 days B) 11 days C) 10 days D) 16 days E) 13 days
C   10 days   Total work to be done = 30 * 40= 
<gadget id="calculator">30 * 40</gadget>
<output>1_200</output>
1200   Let 20 men leave the work after 'P' days, so that the remaining work is completed in 40 days after they leave the work.   40P + (20 * 40)= 1200   40P = 400 =&gt; P = 10 days
<result>C</result>
30 men can do a work in 40 days. When should 20 men leave the work so that the entire work is completed in 40 days after they leave the work?