What was the puzzle?
First thing on which we need to focus on in how much time Jessica and Warner would meet. Since they are moving towards each other the distance of 33 KM is being covered at 5 + 6 = 11 KM/h. So they are going to meet each other in 33/11 = 3 hours. Now everything else here can deceive you to find distance covered by puppy. All you need to do is stick to the basics.
Speed = Distance / Time
Distance = Speed * Time
Distance covered by Puppy = Speed of Puppy * Time for which it traveled.
Distance covered by Puppy = 10 * 3 = 30 KM
So Puppy travels 30 KM to & fro until Jessica and Warner meets.