=1 Here a2=16,b2=25 Focci points =(0,±be)=(0,±√b2−a2) =(0,±√25−16)=(0,±3) Now, from question point P(x,y) lies on the ellipse, then sum of its distance from two fixed points is always constant, equal to length of its major axis. Thus, (PQ+PR)=2×5=10.