39 persons can repair a road in 12 days, working 5 hours a day. In how many days will 30 persons, working 6 hours a day, complete the work?

A. 10 B. 13
C. 14 D. 15

• Let the required number of days be x.
  
  Less persons, More days (Indirect Proportion)
  
  More working hours per day, Less days (Indirect Proportion)
  
  Persons 30 : 39 :: 12 : x
  Working hours/day 6 : 5
  30 x 6 x x = 39 x 5 x 12
  
  x = (39 x 5 x 12)
  (30 x 6)
  x = 13.
• 12 years agoHelpfull: Yes(5) No(2)
• 12/x=30/39*6/5
  x=13
• 9 years agoHelpfull: Yes(0) No(0)
• B.13
  XXXXXX
• 9 years agoHelpfull: Yes(0) No(0)
• (M1 * D1 * H1) / W1 = (M2 * D2 * H2) / W2
  
  Given :
  M1 = 39 M2 = 30
  D1 = 12 D2 = x
  H1 = 5 H2 = 6
  W1 = 1 W2 = 1
  
  now substitute in these values above formula ,
  (39 * 12 * 5) / 1 = (30 * x *6) / 1
  x = (39 * 12 * 5 ) / (30 *6)
  x = 13
  Therefore , 30 persons,working 6 hours a day,complete the work in 13 days.
• 6 years agoHelpfull: Yes(0) No(0)