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) 11 B) 10 C) 19 D) 187 E) 12
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. Answer: 10
<result>B</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?