So, we have..
P(dog) = 29.0 * 2.15 = 62.35 kg m/s
P(cat) = 7.25 * 3.57 = 25.88 kg m/s
P(owner) = 75.4 v = 62.35 + 25.88
v = 1.17 m/s
The direction is
arc tan (2.15 / 3.57) = 31 degrees north of east.
This is the correct answer for A 29.0kg dog is running northward at 2.15m/s , while a 7.25kg cat is running eastward at 3.57m/s . Their 75.4kg owner has the same momentum as the two pets taken together.