1/m+4/n=1/12
Where n is an odd integer less than 60 ??

A. 4
B. 7
C. 5
D. 3

• 1/m + 4/n = 1/12
  Since we know something about n, so express m as the value of n.
  => 1/m = 1/12 - 4/n
  => 1/m = (n-48)/(12*n)
  => m = (12*n)/(n-48)
  
  Now since n is odd +ve integers less than 60.
  So, n must be greater than 48 so than value of m is +ve.
  So range of n is: [49, 59] and only odd numbers.
  Hence, n can be: (49,51,53,55,57,59)
  
  From here we can see clearly that for n = 49, 51 and 57, we get positive integer value for m.
  So there are 3 possible values for pair (m,n)
• 9 years agoHelpfull: Yes(31) No(0)
• Since m and n are positive, n should be greater than 48 ( so that m is positive). So n can be 49, 51, 53, 55, 57, 59.
  
  Let us take each values :
  
  n = 49, m = 12 * 49/1 Both m & n are positive and integers.
  n = 51, m = 12 * 51/3 Both m & n are positive and integers.
  n = 53, m = 12 * 53/5 Both m & n are positive but m is not an integer.
  n = 55, m = 12 * 55/7 Both m & n are positive but m is not an integer.
  n = 57, m = 12 * 57/9 Both m & n are positive and integers.
  n = 59, m = 12 * 59/11 Both m & n are positive but m is not an integer.
• 9 years agoHelpfull: Yes(8) No(6)
• answer D
  
  n is inter and =48.
  
  now for n=48, m=0
  
  for n=52, m=12*13
  
  for n=56, m= 12*7
  
  so only three whole value of m are possible.
• 9 years agoHelpfull: Yes(4) No(1)