P, Q and R can do a work in 20, 30 and 60 days respectively. How many days does it need to complete the work if P does the work and he is assisted by Q and R on every third day?

• (p+Q+r)'s 1 days work=1/20+1/30+1/60=1/10
  p's 2 days work=1/20*2=1/10
  work done in 3 days=1/10+1/10=1/5
  1/5 work done in 3 days
  so 1 work done in 15 days ans
  
• 11 years agoHelpfull: Yes(7) No(0)
• P's 2 day's work = (1/20)*2 = 1/10
  (P+Q+R)'s 1 days work = (1/20+1/30+1/60) = 1/10
  
  total work completed in 3 days = (1/10+1/10) = 1/5
  so 1/5 work is done in 3 days
  1 work is done in 3*5 = 15 days
  
  15 days(Answer)
• 11 years agoHelpfull: Yes(2) No(0)
• work done in every 3 days=2*(1/20)+1/20+(1/30+1/60=1/15
  so, the no. of days=15
• 11 years agoHelpfull: Yes(2) No(1)
• 3/20+1/30+1/60=1/5 [ 3 days work]
  total days =5*3=15
  
• 11 years agoHelpfull: Yes(1) No(0)
• p's 1day work=1/20
  q's 1 day work=1/30
  r's 1 day work=1/60
  so 1st and 2nd day p alone work on the 3rd day all three work
  that is p+q+r 1 days work=1/10
  for 3 days work done is 1/5....(1st day P's work+2nd day P+3rd day p+q+r)
  so the remaining 4/5 work can be done in 12 that equals 15
  ans is 15
• 11 years agoHelpfull: Yes(0) No(0)
• Answer is 15 days
  lets do this problem with efficiency method
  efficiency of a=5,b=3.33,c=1.66=5
  1 day=5
  2 day=5
  3 day=10(3.33+1.66)
  for every 3 days 20% work completed
  so,after 15 days 1005 work completed
• 11 years agoHelpfull: Yes(0) No(0)