A can do a work in 12 hours, B can do in 14 hours. They work alternatively starting from A. A earns rs.15/hr. How much does he earn from the whole job?

a)rs.90
b)rs.165
c)rs.105
d)rs.75

• c) Rs. 105
  
  If A & B each works alternatively for 1 hr., then their 2 hr. work=(1/12)+(1/14)=13/84
  So in 12 hr. 6 times of this work will be completed=6*13/84=39/42, Remaining work=1/14
  Now again A's turn will be to complete next 1/12 work which will he requires 1 hr.
  So A's total work=6+1=7 hr. and earning from the job @Rs. 15/hr= 7*15=105
• 9 years agoHelpfull: Yes(15) No(3)
• Assume total work is 84
  A's 1 day work is 7
  B's 1 day work is 6
  so both can do (A+B)'s 1 day work is 13
  13*6=78
  and 6 is remaining from total wotk
  for 6 days A earned 90
  and for extra 6 work total A earned is 105
• 9 years agoHelpfull: Yes(6) No(3)
• (AB AB AB AB AB AB) A
  (AB AB AB AB AB AB) UPTO THIS 13/14 th of work is done.
  and next is A's turn whose capability is to do 1/12th of work in 1 hr so he does the remaining work which is 1/13th of work.
  So A's turns are 7. so 7*15 =105 rupees
  
  
• 9 years agoHelpfull: Yes(5) No(3)
• I think its c because to complete the work they 12 6/7 days.(1/12+1/14=13/84)so they take 12 6/7 days.so a wrks for 6 6/7 days so 90+12=102
  
  
• 9 years agoHelpfull: Yes(3) No(9)
• ans =(90)
• 9 years agoHelpfull: Yes(2) No(11)
• ANSWER IS 90.
  THEY DO IT ALTERNATIVELY EACH HOUR SO A TOTALLY DOES WORK FOR 6 HOURS AND IS PAID RS 15 PER HOUR SO, 15*6 = 90 IS THE ANSWER.
  WE ARE NOT BOTHERED ABOUT THE 14 HOURS OF WORK DONE BY B AS TAKES ONLY 12 HOURS TO COMPLETE. THE EXTRA 2 HOURS WORK IS DONE BY B NOT BY A.
• 6 years agoHelpfull: Yes(0) No(2)