A and B can compleate a job in 3 and 6 hours respectively.if they work alternatively for 1 hour each,with A starting the job.when will the job be completed?

• A and B can compleate a job in 3 and 6 hours respectively.if they work alternatively for 1 hour each,with A starting the job.
  
  part of work completed on first day by A = 1/3
  part of work completed on 2nd day by B = 1/6
  part of work completed on 3rd day by A = 1/3
  work left = 1-1/3-1/6- 1/3 = 1/6
  part of work completed on 4th day by B = 1/6
  
  so work is completed in 4 days.
• 13 years agoHelpfull: Yes(2) No(0)
• A can do a work in 3 Days so, his efficiency is =1/3;
  B can do a work in 6 Days so, his efficiency is =1/6;
  A and B can do the work in 2 days is (1/3+1/6) is 1/2;
  so, it takes "4" to complete
  
• 13 years agoHelpfull: Yes(1) No(1)