JEE Main202124 Feb 2021Morning ShiftMathematicsSequences and SeriesActual
A man is walking on a straight line. The arithmetic mean of the reciprocals of the intercepts of this line on the coordinate axes is 1 4 . Three stones A , B and C are placed at the points 1 , 1 , 2 , 2 and 4 , 4 respectively. Then which of these stones is / are on the path of the man?
Options
- AC only
- BAll the three
- CB only
- DA only
Correct answer
C. B only
Step-by-step solution
Let the line be y = m x + c x - intercept : - c m y - intercept : c A . M of reciprocals of the intercepts : - m c + 1 c 2 = 1 4   ⇒   2 1 - m = c line :   y = m x + 2 1 - m = c ⇒    y - 2 - m x - 2 = 0 ⇒ line always passes through 2 , 2