If x + y = 109 is the equation of the chord of the ellipse x29 + y24 = 1, whose mid point is ( 52, 12 ). then + is equal to :
- 37
- 46
- 72
- 58
Answer
(4) 58
Solution
Chord with mid-point (x1,y1): T=S1
x(5/2)9+ y(1/2)4-1= 25/49+ 1/44-1 ⇒ 5x18+ y8= 109144
[figure]
× 144: chord 40x+18y=109 ⇒ =40, =18
∴ + =58
Answer: (4)