A can do a work in 12 days.When he had worked for 3 days B joined him. If they complete the work in 3 more days. In how many days can B alone can finish the work?

• Suppose B can complete the work in x days, then
  
  A's 6 days' work = 6/12
  B's 3 days' work = 3/x
  then 6/12 + 3/x =1
  3/x = 1/2
  x = 6
  
  B alone can finish the work in 6 days.
• 12 years agoHelpfull: Yes(26) No(1)
• A 1DAY= 1/12
  A 3DAY= 3/12=1/4
  REMAINING WORK= 1-1/4=3/4
  A+B 3DAY= 3/4
  therefore A+B 1DAY= 3/(4*3)=1/4
  
  B 1DAY= 1/4-1/12
  = 1/6
  B takes 6DAYS.Ans.
• 12 years agoHelpfull: Yes(8) No(1)
• Answer : B can take 6 days to finish the work.
  
  Explanation:
  ------------
  A can do work in 12days alone.
  A=12.
  After 3rd day B joined with A.
  so remaining days to finish the work for A=9(12-3)
  If A & B put the equal amount of effort,
  they both can complete on next 4.5 days.
  But ,they both are completed in next 3days(i.e 6th day)
  So B can work twice as A.
• 12 years agoHelpfull: Yes(2) No(9)
• 12
  a=12
  b=x
  x*12/(x+12)=6
• 7 years agoHelpfull: Yes(1) No(0)