A can do a piece of work in 4 hours . A and C together can do it in just 2 hours, while B and C together need 3 hours to finish the same work. B alone can complete the work in --- days.

Options
1) 12 hours
2) 6 hours
3) 8 hours
4) 10 hours

• A=1/4
  A+C=1/2
  B+C=1/3
  sub a value in 1 eq
  C=3/4
  sub this in eq 2
  B=1/12
  then B can complete work in 12 hours.
  option 1
  
• 8 years agoHelpfull: Yes(2) No(0)
• 1) 12 hours
  
  If A,B and C are the hours required to complete the work individually.
  As A's 1 hr. work=1/4, So (1/4)+(1/C)=1/2, 1/C=1/4
  Also (1/B)+(1/C)=1/3, Substituting value of 1/C, we have 1/B=1/12
  So B alone can complete the work in 12 hours
• 9 years agoHelpfull: Yes(1) No(0)
• 1) 12 hours
  Explanation:
  A & C together takes 2 hours while A alone takes 4 hours
  So, Work done by C alone in 1 hour is, 1/2 - 1/4 = 1/4
  B & C together takes 3 hours
  So, work done by B alone in 1 hour is, 1/3 - 1/4 = (4-3)/12 = 1/12.
  i.e. B alone completes the work in 12 hours
  i.e. half (1/2) day
• 9 years agoHelpfull: Yes(0) No(0)
• a=1/4;
  a+c=1/2; b+c=1/3;
  by solving these two equesion,
  we get,
  b alone can complete the work in 12 hour
• 9 years agoHelpfull: Yes(0) No(0)
• A's one day work is 1/A =1/4
  A and C one day work is 1/A +1/C =1/2
  B and C one day work is 1/B +1/C =1/3
  1/A +1/C =1/2
  substitute 1/A =1/4
  we get 1/C =1/4
  substitute this 1/C value in 1/B +1/C = 1/3
  WE 1/B =1/12
  so b's one day work is 1/12
  B alone can finish the work in 12 days
  option : 1 is the correct answer.
• 9 years agoHelpfull: Yes(0) No(0)
• (A+B+C) can complete the work in=(1/4+1/3)=(3+4/12)=7/12 hrs.
  But B alone can complete in=(7/12-1/2)=(7-6/12)=1/12 hrs.
  So work can be completed in (1/1/12)=12 hours.
  So,(1) is the answer.
• 9 years agoHelpfull: Yes(0) No(0)
• 12
  A do in 4
  a+c in 2
  b+c in 4
  thus we can say that in one day
  a can do 3
  b can 1
  c can 3
  thus alone b can do in 12 hours
  
• 9 years agoHelpfull: Yes(0) No(0)
• Ans. 12 hrs.
  
  A's 1 hr. work = 1/4
  
  A's and C's 1 hr. work = (1/4)+(1/C)= 1/2
  1/C = 1/4
  
  Similarly,
  B's and C's 1 hr. work => (1/B)+ 1/4 = 1/3 ---------(2)
  from eq.(2)
  B's work in 1hr. will be =1/B = 1/12
  So, B's total time taken to complete work = 12 hrs. ANS
• 8 years agoHelpfull: Yes(0) No(0)
• option 2
  6 hours
• 8 years agoHelpfull: Yes(0) No(1)
• A=1/4
  A+c=1/2------(1)
  B+c=1/3-------(2)
  Solve eq.
  A-B=1/6
  Put value of A we get B
  1/12 = 12hours
  
• 8 years agoHelpfull: Yes(0) No(0)