two men can do peice of work in 6 hours and 4 hour respectively. after the first has worked for 2 hours , he is joining by other. by when should tha work be completed?
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1st men do a work in 6hours 2nd men do a work in 4 hours Taking L. C. M of 6,4 6*2= 12 [ men do 2 unit work in 1 hour] 4*3= 12[ men do 3 unit of work in 1 hour] So l. C. M is 12 Therefore total unit of work is 12 unit After this We know that 1st men has worked for 2 hours So 2*2 = 4 [ mean he has done 4 unit of work] After this 8 unit work has left This 8 unit work will done by both So 8\5= 1.6 [ because we know that 2 unit work\hour done by 1st men, and 3 unit work\hour done by 2nd men] Therefor total time taken for work is 2+1.6=3.6hours [Because 1st person has done work 2 hours, and after that both do work in 1.6 hours
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