JEE Mains Model Paper 2

The equation of the ellipse can be written as

x2

25

+

y2

16

= 1
Here a2 = 25 , b2 = 16 but b2 = a2(1−e2)
⇒ 16 = 25 (1 - e2) ⇒ e = 3/5
So that foci of the ellipse are (±ae,0) i.e. (±3,0) or F1 and F2
By definition of the ellipse, since P is any point on the ellipse
PF1+PF2 = 2a = 2 × 5 = 10