Daniel can do some work in 12 hours, Roy can do the same work in 10 hours while Hillari can do the same work in 15 hours. All the three of them start working at 9 a.m while Daniel stops works at 11 a.m and remaining two complete the work. Approximately at what time will the work be finished?

• work done by them in 1 hour each...
  daniel d=1/12,
  roy r=1/10
  hillri h=1/15
  
  work that done if they work for 2hrs ie9am to 11am is 2[1/12+1/10+1/15]
  =1/2
  ie half work is done in 2 hours with d,h,r
  
  now d left the work
  so h,r are there to do remaining work ie half work
  
  work done by h,r in one hour is 1/10+1/15
  =1/6
  
  
  so time taken to do 1/2 work is 3 hours(ie 1/6+1/6+1/6)
  
  therefore by 2pm the total work is done
• 12 years agoHelpfull: Yes(19) No(2)
• please read the question once again
  first two hours all three are
  so 2(1/12 + 1/10 + 1/15) = 1/2
  remaining work 1-1/2 =1/2
  i.e 1/2 of work do the roy and harini [because denial stop the work after two hours ]
  so 1/2=x(1/10 + 1/15),,where x=number of hours for remaining work.
  1/2=1/6 x ====>>x=3 after 11 am they did 3 hours i.e 2 p.m ..
  
• 12 years agoHelpfull: Yes(4) No(0)
• daniel 1hr work is 1/12, roy 1hr work is 1/10 and hillari 1hr work is 1/15
  if all three work together their 1hr work is (D+R+H)=(1/12+1/10+1/15)=1/14
  they start working together at 9 a.m and daniel stops working at 11 a.m..i.e they worked for 2 hrs..the work done in 2hr's is =1/2...remaining 1/2 work is done by hillari and roy..since their 1hr work is (1/10+1/15)=1/6
  1/6 work is done in --> 1hr
  1/2 work will be done in??? i.e 3hrs..so they finish work at 11+3=2 p.m
• 12 years agoHelpfull: Yes(4) No(0)
• solution(in percentage way)---
  consider the whole task as 100.
  Daniel can do some work = 12 hours
  in 1 hour he do the work = (1/12)*100
  =8.33%
  Roy can do some work = 10 hours
  in 1 hour he do the work = (1/10)*100
  = 10 %
  Hillari can do some work = 15 hours
  in 1 hour he do the work = (1/15)*100
  =6.66 %
  working together
  Daniel+Roy+Hillari=24.99 % of work in 1 hour
  now in 2 hours work done by them=24.99*2
  =49.98 % of work
  now work remaining after two hours = 100-49.98
  = 50.02
  now this remaining work is done by Roy and Hillari
  so roy and hillari working together = 10 + 6.66
  = 16.66 % of work
  so they complete 16.66% of work = 1 hour
  time taken by them to complete 50.02% of work = (1/16.66)*50.02 hour
  = 3 hour (aprroximately)
  so tatal time taken by them to complete the work =
  2 hours(working together) + 3 hours (after daniel left)
  = 5 hours(approximately)
  so they will take 5 hours approximately..... hope you will satisfied
• 12 years agoHelpfull: Yes(0) No(13)