Three point charges $q_1$,$q_2$ and $q_3$ are taken such that when $q_1$ and $q_2$are placed close together to form a single point charge, the force on $q_3$ at distance L from this combination is a repulsion of 2 unit in magnitude. When $q_2$ and $q_3$ are so combined the force on $q_1$ at distance L is an attractive force of magnitude 4 unit. Also $q_3$and $q_1$ when combined exert an attractive force on $q_2$ of magnitude 18 unit at same distance L. The algebraic ratio of charges $q_1$, $q_2$, and $q_3$ is