hi, please tell me if you can solve this quiz:

a person, named "x", has taken 30000$ from 3 persons (y,z,t), 10000$ each. he bought a car for 25000$ and left with him 5000$.
then, he gave 1000$ to y, 1000$ to z, and 1000$ to t, and left with him 2000$.
when redoing the calculation, we see that each person has paid 9000$, all three have paid 27000$. when we add to them 2000$ that were with x, they become 29000$. so there is a missing
1000$.
where is that 1000$