Q. If A can do as much work in 4 hours as B can do in 6 hours, or as C can do in 8 hours how long will it take C to complete a piece of work , one third of which has been done by A working 8 hours and B working 18 hours?

• A takes 4hrs to complete x,
  so A does 2x in 8 hrs.
  
  B takes 6hrs to complete x,
  so B does 3x in 18 hrs,
  
  A and B together finshes 2x+3x(=1/3 of y).where y is the new work.
  1/3 0f y=5x,
  so 2/3 of y=10x.
  this is the remaining work for c to do.
  c takes 8 hrs to finish x,so he takes 80 hrs to finish the remaining work.
  
  
• 10 years agoHelpfull: Yes(36) No(1)
• Really a great question
  
  Now This is my way.....
  
  Given that work done by A = work done by B = Work done by C
  
  W/3 2W/3
  *----------------------*-------------------------------------*
  A and B C
  | | |
  / / /
  8 hr 18 hr Let x Hr
  
  A ====== 4 hr => 1/4 work every hour
  B ====== 6 hr => 1/6 work every hour
  C=======8 hr => 1/8 work every hour
  
  that means
  
  8/4 + 18/6 = W/3
  
  => W= 15 Units
  
  Similarly
  
  x/8 = 10 ( (2*15)/3 = 10)
  
  => x = 80 hr
  
  
• 9 years agoHelpfull: Yes(8) No(1)
• let A can complete x% work in 1 hour
  
  so B can complete 4x/6 % work in 1 hour
  similarly C can complete 4x/8% work in 1 hour
  
  in 8 hours A can complete 8x% work
  and in 18 hours B can complete (4x/6)*18 % = 12x% work
  
  since one third or 100/3 % work has been done
  100/3 = 8x + 12x
  which gives x = 5/3%
  
  so C's 4x/8% work will become 5/6%
  
  now C is completing 5/6% work in 1 hour
  100*(2/3) work will be completed in 80 hours
• 10 years agoHelpfull: Yes(6) No(1)
• let A does a% of work in 1h;
  similarly B in 1h b% and C in 1h c%;
  
  now
  4a=6b=8c; (say equation 1)
  
  8a+18b=33.33
  40c=33.33; (from equation 1)
  c=33.33/40
  
  t.c=66.66
  t=66.66/c
  t=66.66*40/33.33
  t=80;
  
• 9 years agoHelpfull: Yes(3) No(0)
• c completes the work in 120 hrs.
• 6 years agoHelpfull: Yes(0) No(0)
• A takes 4hrs to complete x,
  so A does 2x in 8 hrs.
  
  B takes 6hrs to complete x,
  so B does 3x in 18 hrs,
  
  A and B together finshes 2x+3x(=1/3 of y).where y is the new work.
  1/3 0f y=5x,
  so 2/3 of y=10x.
  this is the remaining work for c to do.
  c takes 8 hrs to finish x,so he takes 80 hrs to finish the remaining work
• 6 years agoHelpfull: Yes(0) No(0)