Each of A,B,C need a certain unique time to do a certain work.C needs 1hr less than A to complete the work.Working together they require 30min to complete 50percent of the job.The work also gets completed if A & B start working together and A leaves after 1hr and B works for further 3 hrs.How much work does C do per hour?
a)16.6%
b)33.3%
c)66.6%
d)50%

• Suppose A takes A hrs,B takes B hrs.C wud take (A-1) hrs
  
  Work done by A in 1/2 hrs=1/2A,B=1/2B,C=1/2(A-1)
  Hence (1/2A)+(1/2B)+{1/2(A-1)}=1/2.......(i)
  
  Also,wen A n B work,A works for 1 hr and B for 4 hrs..
  Hence...(1/A)+(4/B)=1....(ii)
  
  Solve (2) and get 1/B in terms of A..Put values of 1/B and 1/C in (1) and solve,u vl get a quadratic equation..Solve it and A=3 hrs
  
  C=A-1 hrs= 2 hrs...Hence in 1 hr,C does 1/2 of work or 50%
• 11 years agoHelpfull: Yes(17) No(2)
• Let us consider the time taken by A be x hours.
  Then A = 1/x; C = 1/(x-1)
  Working together they required 30 mins to complete 50 % of the work.
  So, they will take 1 hour to complete the whole work.
  A + B + C = 1/1=1 - - - (1)
  1*(A+B) + 3B = 1
  B = (1-A)/4
  = (1/4)-(1/4x)
  By substituting the values of A, B and C in (1),
  x=1/3 or 3.
  A have taken more than one hour. so, x=3 hours and hence C have taken x-1=2 hours.
  So, C can complete 50% of the work per hour.
  
• 10 years agoHelpfull: Yes(1) No(2)
• pls send me all questions u have i have apti on 22 sept mumbai id- tjroxxy@gmail.com
• 11 years agoHelpfull: Yes(0) No(4)