Explanation:

- Tree M is 3 km west of N.

- P is 2 km north of M.

- O is 3 km east of P.

- Q is 6 km south of O.

- N is directly between O and Q.

- S is between M and R, 2 km from M.

- T is 3 km west of S.

- U is north of T, equidistant from T as S is from P.

Let's visualize:

- Imagine a basic coordinate setup.

- Using coordinates with M at (0,0):

- M: (0,0)

- N: (3,0) east from M

- P: (0,2) north from M

- O: (3,2) east from P

- Q: 6 km south from O at (3,-4)

- N is in between O (3,2) and Q (3,-4).

Now, concerning the distance between M and R:

- S is 2 km from M, and R is directly past S at 2 more km.

Therefore, the distance between M and R is 4 km.