The circumference of the circle x2+y2−2x+8y−q=0 is bisected by the circle x2+y2+4x+12y+p=0, then p+q is equal to
Common chord of the 2 circles is given by
S1–S2=0
⟹6x+4y+(p+q)=0
Since S2 bisects S1, center of S1 lies on common chord.
⟹6(1)+4(−4)+p+q=0
p+q=10