If A can complete a work in 12 days, B in 5 days, then find the time (in days) taken by them in each of the cases listed below :

(a) When and work together.

(b) When and work alternatively, and work is started by A.

(c) If starts two days later, in comparison to A

• A can complete work in one day is 1/12
  B can complete work in one day is 1/5
  A+B can complete work in one day is (1/12)+(1/5)=17/60.
  case (1):When work together
  A+B can complete work in (60/17)=3.52=4days
  case (2):When and work alternatively, and work is started by A.
  assume total work is 1
  A can complete the work in first day = 1/12
  B can complete the work in second day = 1/5,total work=(1/12)+(1/5)=17/60.
  so we can conclude that no of days is double the,when they work to gether so that 8days
  case(3):If starts two days later, in comparison to A
  A two days work is 1/6,so that remaing work 5/6 is completed in they work together,A+B can complete work in one day is (1/12)+(1/5)=17/60 remaing work completed in number of days = (60*5)/(6*17) =2.94 days,so that 3 days overall work completed in 5 days.
  
  
  
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