A contractor hires 100 men to finish a job in 50 days. After 40 days, n men leave. After some more days, the contractor hires 2n more men to complete the job on time. For how many days did these 2n men work?
Options:
A) 20	B) 18	C) 16	D) 12	E) 5
Step1: Find Each day what % of work is finished ; it requires 50 days to complete which means each day 1/50= 2% work will be completed.   Step 2 : After 40 Days = 40* 2= 
<gadget id="calculator">40* 2</gadget>
<output>80</output>
80% of work is finished. remaining is 20% ( which means if same 100 men were about to complete the job they would have required 10 more days)   Step3: Let us assume all people have left job. therefore contractor hires 2n people. initially it was taking 10 days to compete for n people. at present 2n people are present to finish job. hence 5 more days.   5
<result>E</result>
A contractor hires 100 men to finish a job in 50 days. After 40 days, n men leave. After some more days, the contractor hires 2n more men to complete the job on time. For how many days did these 2n men work?