JEE Main2014MathematicsStraight LinesActual
Given three points P , Q , R with P 5 , 3 and R lies on the x - axis. If the equation of R Q is x - 2 y = 2 and P Q is parallel to the x - axis, then the centroid of Δ P Q R lies on the line
Options
- Ax - 2 y + 1 = 0
- B2 x + y - 9 = 0
- C2 x - 5 y = 0
- D5 x - 2 y = 0
Correct answer
C. 2 x - 5 y = 0
Step-by-step solution
Given, P 5 , 3 and equation of R Q is x - 2 y = 2 ⇒   R ≡ 2 , 0 lies on x - axis and Q lies on a line parallel to x - axis through P which is y = 3 . Hence, on solving y = 3 and x - 2 y = 2 ⇒ x = 8 ∴    Q ≡ 8 , 3 Centroid ≡ 5 + 8 + 2 3 , 3 + 3 + 0 3 ≡ 5 , 2 ∵   x 1 + x 2 + x 3 3 , y 1 + y 2 + y 3 3 5 , 2 lies on   2 x - 5 y = 0