x is a real number, attains a minimum at

Replies

• 

  Saandeep Sreerambatla

  Is it 2.9? Notsure though!!
• 

  rengaraj

  Dear English,
  Can you explain your answer?
  The choices are 2.5,2.7,2.3,None of These
  R.Rengaraj
• 

  limestone7000

  my first step would be to club the 2nd and 3rd terms
  so,
  |2.5 - x| + |3.6 - x|
  = |6.1 - 2x|
  
  now,
  f(x) = |x - 2| + |6.1 - 2x|
  
  by observing, x shouldn't be negative if u want minimum value of f(x),
  so, x>0
  
  now,
  for x = 2.3, f(x) = 1.8
  for x = 2.5, f(x) = 1.6
  for x = 2.7, f(x) = 1.4
  [observe that as the value of x increases, value of f(x) decreases]
  2.7 could be the answer, but to verify, lets take x = 2.9
  so, f(x) = 1.2 for x = 2.9!!!!
  
  hence, the answer is NONE OF THESE!
  😀
• 

  rengaraj

  Dear Limestone,
  Excellent reply.
  Keep it up.
  R.Rengaraj
• 

  tdave

  "observe that as the value of x increases, value of f(x) decreases" so x=2.9!
  
  it really take me some time..
• 

  anu_mech

  i suppose u cant club 2.5-x and 3.6-x. 'cause if x is between 2.5 and 3.6 one positive and the other negative
  observe the function its value is
  f(x)= 8.1-3x (for x<2)
  =4.1-x (for 2 =x-.9 (for 2.5 =3x-8.1 (for x>3.6)
  
  plot the graph and u get....2.9
• 

  HImanshu_Sharma

  yeah limestone is right