Each of A,B and C need a
certain unique time to do certain work. C needs 1 hour less than A
to complete the work. Working together they require 30 minutes to
complete 50% of the work. The work also gets completed if A and B
start working together and A leaves after 1 hour and B works further
3 hours. How much work does C do per hour?
a. 16.66%
b. 66.66%
c. 50%
d. 33.33%

• 50% suppose A do work in x hrs ,B in y, then c would do in x-1 hrs..then 1/x+1/x-1+1/y=1 in 1 hrs..also A&B 1 hrs work 1/x+1/y then work remaining xy-x-y/xy which is done by B in 3 hrs so (xy-x-y)/xy=3/y it results y=4x/x-1 putting value we get x=3 so y=6 so A CAN DO WORK in 3 hrs B in 6 hrs & C IN 2 hrs that is 50%
• 11 years agoHelpfull: Yes(16) No(8)
• 50 % work done by c per hour
• 11 years agoHelpfull: Yes(3) No(14)
• correct ans will be 61.7%...dere is sme mistake in d option
• 11 years agoHelpfull: Yes(3) No(11)
• @mohibullah plz explain..!
• 11 years agoHelpfull: Yes(2) No(4)
• Let A take 'a' hours to complete the work alone.
  Then C takes (a-1) hours to complete the work alone.
  In 1 hour 'A' completes 1/a of the work.
  In 1 hour 'C' completes 1/(a-1) of the work.
  Both together complete 1/a + 1/(a-1) = (2a-1)/a(a-1) of the work in 1 hour.
  A & C together need a(a-1)/(2a-1) hours to complete the work.
  Now A & C together complete 50% of work in 30 minutes
  So A & C together complete 100% work in 1 hour.
  Therefore a(a-1)/(2a-1) = 1
  solving, a= {3(+/-)√(5)}/2
  C takes one hour less than A to complete the work, which can not be -ve. So we can discard a=(3 - √5)/2 .
  Hence a=(3 + √5)/2 .
  So 'C' takes (a-1) = (1+√5 )/2 hours to complete the work.
  In one hour 'C' will complete 2/(1+√5 ) = 2/3.24 = 0.66 of work
  = 66%
• 6 years agoHelpfull: Yes(2) No(2)
• plz explain...
  
• 11 years agoHelpfull: Yes(1) No(6)
• @ASHISH right 61.8%
• 11 years agoHelpfull: Yes(0) No(6)
• balendu narain pandey
  u cannt assume they together did the work in 1 hr.u r wrong
• 11 years agoHelpfull: Yes(0) No(6)