A $992$ kg red car is travelling to the east at a speed of $47\mathrm{.}7$ m$/$s and a $1\mathrm{.}50\backslash$times $103$ kg blue car is travelling $30\mathrm{.}0\backslash$deg south of west at a speed of $11\mathrm{.}9$ m$/$s$.$ They collide and then continue to move while attached to each other. What is the speed of the two cars together?