a father is 5 times as faster as son in doing a work. Father completes a particular work in 40 days before son.If both of them work together in how many days can they complete the work?

• Son=x
  father=5x
  5x-x=40
  x=10
  1/50+1/10=3/25
  So,25/3 days
• 10 years agoHelpfull: Yes(58) No(5)
• f=5*s
  
  f(t-40)=w=s*t
  5*s*(t-40)=s*t
  5t-t=200
  t=50
  father takes 10 day
  son takes 50 days
  together=50/6=8.33days
• 10 years agoHelpfull: Yes(17) No(5)
• Say father(F) and son(S) and time taken(t)
  F=5S (given)
  t and t+40days are durations taken by father and son to complete the work respectively.
  Workdone=W=F*t=S*(t+40)
  F*t=S*(t+40)
  (5*S)*t=S*(t+40)
  t=10days.
  So,time taken by father is t=10days and son(t+40)=50days.
  When both of them work together:::
  [Choclate method: Lcm of 10days and 50days is 50.(50 choclates say)
  Choclates consumed by son is 50/50=1(choc/day)
  an father is 50/10=5(choc/day)
  total chocs consumed by both of them in 1day is 6.
  Then 50 choclates can be consumed in 50/6=8.33days}
  So,therefore both of them working together can finish it in 8.33days.
  
• 10 years agoHelpfull: Yes(15) No(4)
• f=5s
  1/f=1/s-40
  s=1/50 time(s)=1/s=50
  f=1/10 time(f)=1/f=10
  1/f+1/s=25/3 days
• 10 years agoHelpfull: Yes(8) No(3)
• think abt it guys...can adding and efficiency 1/5 th the original reduce the 40 days to 8.33????
  
  
  let,rate od doing wrk fr son be 1/s per day
  so for father it is, 5/s
  time for father to do a unit of wrk is s/5,which is 40 days
  hence s=200
  
  together, 5/s+1/s=6/s or 6/200= 33.33 days
• 10 years agoHelpfull: Yes(7) No(9)
• given:efficiency--> father/son=5:1
  so let son completes the work in x days
  then
  father will do in (x-40)days.
  as we now no. of days is inversely prportional to efficiency i.e more the efficient person is less time it will take to do the work...
  hence we have x/5=(x-40)
  by this we got x=50 i.e boy takes 50 days.
  so father takes = (50-40)=10 days
  
  if they do work together then they complete the work in-->
  1/50+1/10-->3/25
  hence no. of days for completion= 25/3=8.33 days
  
  
• 10 years agoHelpfull: Yes(7) No(0)
• total work will be 50
  hence time duration=50/6=8.33 days
  
• 10 years agoHelpfull: Yes(3) No(10)
• consider that son did his work in x days,then father would do it in x/5 days.
  so 5/x - 1/x = 1/40 then x=160 and father completes his work is 32days.together they can do it in 1/32 + 1/160 = 80/3days
• 10 years agoHelpfull: Yes(3) No(3)
• efficiency of father 1/40= 2.5%
  efficiency of son 2.5/5= .5%
  overall efficiency = 2.5+.5=3%
  therefore no. of days= 100/3=33.33
• 10 years agoHelpfull: Yes(2) No(6)
• let son does d work in 50days & father does it in 10 days
  therefore efficiency of son 2% and efficiency of father 10%
  therefore total no of days= 100/(10+2)=8.33%
• 10 years agoHelpfull: Yes(1) No(0)
• 1/x-1/5x=1/40
  x=32
  
• 10 years agoHelpfull: Yes(0) No(5)
• let son completed any work in x days so father complt the same work in x-40 days...
  so..
  1/(x-40)=5/x;
  x=50;
  now 1/50+1/10=3/25;so ans.=25/3;
• 9 years agoHelpfull: Yes(0) No(0)
• Son=x
  father=5x
  5x-x=40
  x=10
  1/50+1/10=3/25
  So,25/3 days
• 8 years agoHelpfull: Yes(0) No(0)