12 boys working on a work, which takes 18 days to get completed. after six days of working, 4 boys joined with them . how many days it takes to complete the remaining work?
option
a)none
b)10
c)8
d)9

• d) 9
  12 boy 1 day work= 1/18, so
  12 boy 6 days work=6/18=1/3, Remaining work=2/3
  4 boy 1 day work= 1/(18*3)=1/54
  Total work of (12+4) boys,1 day = 1/18 + 1/54 = 4/54= 2/27
  So days to complete remaining 2/3 work= (2/3)*(27/2)=9
• 11 years agoHelpfull: Yes(16) No(3)
• Work = men * days, so 12*18=216(total work).for six days work =6*12=72. so work remaining = 216-72=144 now 4 more boys joined so more days required = 144/16 days,which is 9 days.
• 11 years agoHelpfull: Yes(5) No(0)
• a)none
  18*12=216,for 6 days 12*6=72,216-72=144,now 4 boys joined them,therefore
  days=144/16=9,and they have already done for 6 day therefore 6+9=15
• 11 years agoHelpfull: Yes(0) No(1)
• 12 boys will complete a work in 18 days.
  1 boy will complete a work in 216(18*12) days.
  
  1 boy's 1 day work = 1/216
  1 boy's 6 days work = 6/216 = 1/36
  12 boy's 6 days work = 12/36 = 1/3
  
  so, 1/3 work is completed in 6 days by 12 boys.
  
  remaining work = 1-1/3 =2/3.
  
  After 6 days 4 boys has joined.
  
  16 boys will do the 2/3 work in 9 days.
• 11 years agoHelpfull: Yes(0) No(0)