A solution of urea in water has a boiling point of \( 100.18^\circ C \). What is the freezing point of the same solution, if \( K_f \) and \( K_b \) of water are \( 1.86 \) and \( 0.52 \) K kg mol\(^{-1} \), respectively? (Boiling point of water = \( 100^\circ C \))