A, B and C can finish a work independently in 10, 12 and 15 days. C starts the work and after 1 day, B joins him. After 1 day of B, A also joins them but leave 3 days before completion of the work, while B left two days before completion of work. What will be the total number of days taken to complete the work?

• 7 days
  
  Let the work is completed in 'x' days, then
  C worked for 'x' days
  As B joins after 1 day of C and left 2 days before completion of the work, so B worked for 'x-3' days.
  A joins after 1 day of B, i.e. 2 days after C and left 3 days before completion of the work, so A worked for 'x-5' days
  => [(x-5)/10] + [(x-3)/12] + (x/15) =1
  => (12x-60+10x-30+8x)/120 =1
  => 30x =210
  => x= 7
• 8 years agoHelpfull: Yes(1) No(0)