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← JEE Main 2026 · 2 Apr · Shift 1
MathematicsSingle correct+4 / -1Question 9 of 75

JEE Main 2026 · 2 Apr · Shift 1, Mathematics question 9

Let the mid points of the sides of a triangle ABCABC be (52,7)\left(\frac52,7\right), (52,3)\left(\frac52,3\right) and (4,5)(4,5). If its incentre is (h,k)(h,k), then 3h+k3h+k is equal to :

Choose one option
Answer and worked solution

Official answer: C

Vertices from midpoints. The vertices sum to the midpoints' sum (9,15)(9,15); each vertex is that sum minus twice the opposite midpoint: (4,1)(4,1), (4,9)(4,9), (1,5)(1,5).

Sides. Opposite (4,1)(4,1): 5. Opposite (4,9)(4,9): 5. Opposite (1,5)(1,5): 8.

Incentre.
5(4,1)+5(4,9)+8(1,5)18=(83,5),3h+k=8+5=13.\frac{5(4,1)+5(4,9)+8(1,5)}{18}=\left(\frac83,5\right),\qquad3h+k=8+5=13.

(C)