A B C CAN DO A PIECE OF WORK IN 20,30,60 DAYS RESPECTIVELY. IN HOW MANY DAYS A CAN DO THE WORK IF HE ASSISTED BY B AND C EVERY THIRD DAY

• A's 1 day work = 1/20
  B's 1 day work = 1/30
  C's 1 day work = 1/60
  
  A's 2 days' work = 2*1/20 = 1/10, and
  (A+B+C)'s 1 day's work = 1/20 + 1/30 + 1/60 = 1/10
  
  Now, (A+B+C)'s 3 days' work = A's 2 days' work + (A+B+C)'s 1 day's work
  = 1/10 + 1/10 = 1/5
  
  So, 1/5th work done in 3 days, so
  Whole work done in 3/(1/5) = 3*5 = 15 Days
  
  Answer: 15 Days
  
• 10 years agoHelpfull: Yes(54) No(0)
• let the work to be 100%
  
  A's efficiency= 5%/day
  B's efficiency=3.33% /day
  C's efficiency=1.66% /day
  
  
  (A+B+C)'s 3 days work= A's 2 days work + (A+B+C)'s 1 day work
  (5%*2)+(5%+3.33%+1.66%)=20%
  
  if, 20% work is completed in 3 days
  so 100% work will be completed in 15 days
• 10 years agoHelpfull: Yes(8) No(0)
• A's 2days work=1/20*2=1/10
  A,B,C 1 day work=1/20+1/30+1/60=1/10
  work done in 3 days=(1/10+1/10)=1/5
  total work done(3*5)=15days
• 10 years agoHelpfull: Yes(5) No(0)
• here AS 2 days work =1/20*2=1/10 and abc together one day wok=1/10 workdone in 3 days is 1/5 so 1/5 th of work is done in 5*3 =15days
• 10 years agoHelpfull: Yes(2) No(0)
• here as 2 days work =1/20*2=1/10 and abc together one day work =1/10, work done in 3 days =1/5 so 15th of work in 3 days and full work will be done in 15 days
• 10 years agoHelpfull: Yes(2) No(1)
• A's 2 days work =1/20*2=1/10 and abc together 1 day work is 1/10 workdone in 3 days is 1/5th so 1/5th workdone in 3 days full work in 15 days
• 10 years agoHelpfull: Yes(2) No(0)
• 
  A's 2 day's work =(1x 20)/2=1/10
  
  (A + B + C)'s 1 day's work =(1/20+1/30+1/60)=6/60=1/10
  
  Work done in 3 days =(1/10+1/10)=1/5 .
  
  Now, 1/5 work is done in 3 days.
  
  hence, Whole work will be done in (3 x 5) = 15 days.
• 10 years agoHelpfull: Yes(1) No(0)
• A= 20 days
  B= 30 days
• 10 years agoHelpfull: Yes(0) No(4)
• A 2 day work is=(1/20)*2=1/10
  A,B,C oneday work is(1/20+1/30+1/60)=(3+2+1)/60=1/10
  3 day work is(1/10+1/10)=(1/5)
  totally 5*3=15days
• 10 years agoHelpfull: Yes(0) No(0)
• A=20days
  B=30days
  C=60days
  
  Assume total work=120units
  Rate of work of 'A'=120/20=6units/day
  Rate of work of 'B'=120/30=4units/day
  Rate of work of 'C'=120/60=2units/day
  
  In 1 day A =6units of work
  in 1 day B=4units of work
  in 1 day C= 2 units of work
  
  Assume in 1 turn=work done by A in 1st day+work done by A in 2nd day+work done byA+B+B+C in 3rd day=24units
  1 turn=24units of work is done
  therefore, in 5 turns =120units can be done(assumed total work)
  1 turn=3days
  5 turns =15 days
  
  ans=15days
• 5 years agoHelpfull: Yes(0) No(0)