Let the mid points of the sides of a triangle ABC be (25,7),(25,3) and (4,5). If its incentre is (h,k), then 3h+k is equal to :
(A)11
(B)12
(C)13✓ Correct
(D)14
Answer: (C)
Solution
If the vertices are A,B,C, the midpoints give (coordinatewise) B+C=(5,14), A+C=(5,6) and A+B=(8,10). Adding, 2(A+B+C)=(18,30), so A+B+C=(9,15); subtracting each pair yields A=(4,1), B=(4,9), C=(1,5). The sides are a=BC=32+42=5, b=CA=32+42=5 and c=AB=02+82=8. The incentre is (a+b+caAx+bBx+cCx,a+b+caAy+bBy+cCy)=(185⋅4+5⋅4+8⋅1,185⋅1+5⋅9+8⋅5)=(38,5). Therefore 3h+k=3⋅38+5=13.
JEE Main · 2026 · 02 Apr 2026 · Shift 1 · Single correct option