Answer
$K = 11.6~eV$
Work Step by Step
We can find the energy when the atom is in the n=2 state:
$E = \frac{E_0}{n^2}$
$E = \frac{-13.6~eV}{2^2}$
$E = -3.4~eV$
The energy required to remove the electron from the atom is $3.4~eV$. We can find the kinetic energy of the electron after it is removed from the atom:
$K = 15.0~eV-3.4~eV = 11.6~eV$
