How many different wavelengths?

Question

Eventually, all of the excited hydrogen atoms will emit photons until they fall back to the ground state. How many different wavelengths can be observed in this process?

Going from n=5 to ground state.

Answer 1

10 wavelengths

5-->4  

5-->3

5-->2

5-->1

4-->3

4-->2

4-->1

3-->2

3-->1

2-->1