Alex and John can separately do a piece of work in 14 and 11 days each. They start working together on this and later, John leaves. After this, Alex completes the work in 8 days. For how many days did Jonh work?

• Alex completed 8/14 work in 8 days.
  
  Earlier, John and alex completed 6/14 or 3/7 work together in (3/7)/(25/154) = 66/25 days
  
  so john worked for 66/25 days along with alex.
• 12 years agoHelpfull: Yes(0) No(0)
• For simplification, let the total work be 154 units of work
  Let both work together for x days before John left
  Thus John worked for x days and Alex worked for x+8 days
  In one day John can complete 154/11=14 units of work
  Thus in x days John can complete =14x units of work
  Similarly, John can complete in x days= 11x units of work
  Thus, they both completed in x days =14x+11x=25x units of work
  Now, the balance work was completed by Alex in 8 days.
  It implies, that Alex completed in 8 days=11*8=88 units of work
  Thus the balance work (154-88)=66units of work in x days by both of them
  Alex and John together in one day can complete 14+11=25units
  Thus, they have worked together for 66/25 days
  
• 12 years agoHelpfull: Yes(0) No(0)