a can do a piece of work in 20 days he works at it for 5 days.and b finishes it in 10 more days.in how many days a and b work together to finish the work...

• A one day work is 1/20
  for 5 days=5*(1/20)=1/4....that is this much of work is already done
  remaining work is 3/4
  B works for remaining work....3/4 work is completed in 10 days..then total work B alone can complete in how many days is....10*(4/3)=40/3 days
  A and B combined work in 1 day=1/20 + 3/40=5/40=1/8
  therefore total work will be done in 8 days
• 11 years agoHelpfull: Yes(29) No(0)
• Work done by a in 5 days= 1/20 *5 = 1/4
  Remaining work = 1-1/4= 3/4
  3/4 work is done by b in 10 days.
  Whole work is done by b in 10 x 4/3= 40/3 days
  so (a+b)'s 1 day work = 1/20 + 3/40 = 5/40 = 1/8
  so they can complete the work together in 8 days.
• 11 years agoHelpfull: Yes(6) No(0)
• Let the total work be 120. A can do 6 everyday.So, in 5 days he can complete 30 and B completed the remaining 90 in 10 days.
  So, rate of B= 9
  Total time taken by a and B together to finish the work of 120 = 120/(6+9) = 120/15 = 8 days
  Answer is 8 days
• 11 years agoHelpfull: Yes(4) No(2)
• 8days
  1/4 work done by a in 5 days. rest 3/4 work will be done by b in 10 days . so (1/20)+(3/40)=1/8
  ie in 8days
  
  
• 11 years agoHelpfull: Yes(2) No(0)