A & B together can complete the work in 30 days.If after working for 4 days, they take the help of C and D on each alternate days and manage to complete the work in 9 days.If D is twice as efficient as C. In how many days D alone can complete the work ?

• @ Devendra,
  
  Pls confirm whether C&D work together on alternate days or each one work on alternate days . whether total work is completed in 9 days or 4+9=13 days ?
• 11 years agoHelpfull: Yes(2) No(1)
• ans :5 days
  4/30+3(1/30+1/2x)+2(1/30+1/x)=1 here x=d's work days 2x=c's work days
  x=5
• 11 years agoHelpfull: Yes(2) No(1)