Amy's weight = 55 kg also Amy's velocity = 3 m/sec. And Jenny's weight = 40 kg Jenny's velocity = -5 m/sec. their final mass = 55+40 = 95 kg is their final velocity that we want to find out. Ect. but in conclusion the answer is 7/19 m/sec.
I hope this is correct >w< if it's not I am really sorry I mist up.