JEE Main 2025 Mathematics question
Let the triangle PQR be the image of the triangle with vertices (1,3), (3,1) and (2, 4) in the line x + 2y = 2. If the centroid of ΔPQR is the point (α, β), then 15(α – β) is equal to :
Answer: (4)
Solution
Centroid of original triangle is (2, 8/3). Reflecting this point across x+2y-2=0 gives (α,β) = (-2/15, -24/15). So 15(α-β) = -2+24 = 22.