30 girls finish a work in 40 days. after how many 10 girls be permitted to leave so that work gets completed in 46 days ?

• 28 days.
  
  30*40 = 1200
  
  30*28 + 20*18 = 840 + 360 = 1200
• 10 years agoHelpfull: Yes(0) No(0)
• Let 30 girls did the work for x days.
  It means (46-x) are remained for 20 girls.
  
  Total work is 30 girls * 40 days = 1200 girls-days
  
  So, 30x+(46-x)20 = 1200
  x=28
• 10 years agoHelpfull: Yes(0) No(0)