Balmer gives an equation for wavelength of visible radiation of H spectrum as λ=kn²/(n²-4). The value of k in terms of Rydberg's constant R is?

Generally the wavelength for Balmer series is given by,
1/λ=R(1/2² - 1/n²)
Now substituting the value of λ given in above expression,
n²/(kn²) = R(1/2² - 1/n²)
or
n²/(kn²) = R[(n²-4)/4n²]
ork=4R