1/x+1/y=1/z where x=12 and y,z positive integer how many possible value of y and z ?
a) 4
b) 7
C) 12
d) infinite

• I think the answer would be 7. Y=(12*Z)/(12 - Z). Hence, Z cannot be more than 12. The permissible values of z are 11,10, 9, 8, 6, 4, 3. Hence, the answer is 7. Correct me if I am wrong.
  
• 8 years agoHelpfull: Yes(32) No(8)
• infinite values are possible
• 8 years agoHelpfull: Yes(12) No(25)
• INFINITE solution is possible, we can take the several values of of y in 1/12+1/y such that
  1/12+1/y=1/z
  12y/12+y=z
  in this eq. we put positive integer of y and and on many positive integer value of y we will get the many positive value of z so infinite solutions
• 8 years agoHelpfull: Yes(8) No(4)
• 1/x + 1/y = 1/z
  
  or 1/y = 1/z - 1/12
  
  or y = 12z / (12-z)
  
  Solving for y and z ;
  
  For, z = 3 , y = 4
  
  For, z = 4 , y = 6
  
  For, z = 6 , y = 12
  
  For, z = 8 , y = 24
  
  For, z = 9 , y = 36
  
  For, z = 10 , y = 60
  
  For, z = 11 , y = 120
  
  Z can not excceed 11 as for z = 12 , y = infinite and for z > 12 y will be negative
• 7 years agoHelpfull: Yes(4) No(1)
• Ans is 7
  1/x + 1/y = 1/z
  
  or 1/y = 1/z - 1/12
  
  or y = 12z / (12-z)
  
  Solving for y and z ;
  
  For, z = 3 , y = 4
  
  For, z = 4 , y = 6
  
  For, z = 6 , y = 12
  
  For, z = 8 , y = 24
  
  For, z = 9 , y = 36
  
  For, z = 10 , y = 60
  
  For, z = 11 , y = 120
  
  Z can not excceed 11 as for z = 12 , y = infinite and for z > 12 y will be negative
• 6 years agoHelpfull: Yes(3) No(0)
• INFINITE VALUES:
  
• 8 years agoHelpfull: Yes(2) No(3)
• Ans. (d)infinite
  Explanation:
  1/12+1/y=1/x
  y+12/12y = 1/z
  for every values of Y multiple of 12 i.e y= 12,24,36,48 and so Z will be an Integer
  
• 8 years agoHelpfull: Yes(2) No(4)
• (c) 7 is the correct answer
  
  y = (12*z)/(12-z) => value of z greater than 12 will result into negative value of y. therefore z cannot be greater than 12.
  
  1/y= 1/z-1/12
  =>for z=3 ,4,6,8,9,10,11 -------- 7 values
  (for z=12 y=0 and 0 is not a positive integer and in question it asks for positive integer so this will not be considered)
• 7 years agoHelpfull: Yes(2) No(0)
• option b(7) is correct answer, infinite solutions are not possible as y and z are positive and integer
• 6 years agoHelpfull: Yes(1) No(1)
• for,
  1/12=1/z-1/x and z
• 8 years agoHelpfull: Yes(0) No(1)
• @Anjali Gupta
  Can u pls explain how?
• 8 years agoHelpfull: Yes(0) No(0)
• from the equation we get,
  
  y = (12 * z) / (12 - z)
  
  Hence , when z=12 the value of y is infinity and beyond z=12 i.e in z=13,14...and so on y becomes a
  -ve integer which cannot be the case.
  So correct ans is 12.
  as the range of z is from 0 - 11.
• 5 years agoHelpfull: Yes(0) No(0)