How much do the 3 animals weigh together?

As you can see in the drawing, we know the weight of the dog + cat, the weight of the cat + mouse, and the weight of the dog + mouse.

Could you tell how much the dog + cat + mouse weigh?

If you find yourself stuck, don't worry! Here's a Clue

If you seek the answer, you can find it here: Solution

There are several ways to solve the riddle; here's one of the easiest. 😉 How to solve it?