Two radioactive substances X and Y originally have `N_(1)` and `N_(2)` nuclei respectively.Half life of X is half of the half life of Y .After three half lives of Y ,number of nuclei of both are equal.The ratio `(N_(1))/(N_(2))` will be equal to :
(1) `(1)/(8)`
(2) `(3)/(1)`
(3) `(8)/(1)`
(4) `(1)/(3)`