As the midpoint of the chord is `(0,3)`, endpoints of the chord can be,`(a,3) and (-a,3)`.
Then, the length of the chord` = 2a`
As point `(a,3)` lies on the ellipse, it should satisfy the equation.
`:. a^2/16+3^2/25 = 1`
`=>a^2/16+9/25 = 1`
`=>a^2/16 = 16/25=> a =+-16/5`
We are fiven length of chord is `(4k)/5`.
`:. |2a| = (4k)/5 => |a| = (2k)/5`
`=> (2k)/5 = 16/5 => 2k = 16=> k =8`
