Merhaba! I am still studying Turkish, but now I have reached a point where I am confronted with choices but don´t always know which path to take. For instance, my exercise book asked me to translate this sentence:

Since Mehmet didn´t come, I hope that Ahmet won´t come either.

This was my try: Mehmedin gelmediğiden dolayı, Ahmedin gelmeceğini ümit ederim.

This was the book´s answer: Mehmet gelmediği için Ahmedin de gelmiyeceğini ümut ederim.

Is the way I wrote the sentence a legitimate choice, or am I off the tracks here?

Teşekkürler!

Your translation is not wrong. It just needs a small correction.

Mehmet gelmediğinden dolayı, Ahmet´in de gelmemesini ümit ederim.

Mehmet is subject there. Because [since] Mehmet did not come ---> we don´t put possessive  [in] on Mehmet. 

Mehmet gelmediği için Ahmet´in de gelmeyeceğini ümit ederim.

more natural way would be;

 Mehmet gelmediği için inşallah [umarım] Ahmet de gelmez. 

Thank you, all. I will keep working on this. ... Also, I am glad to know about not making Mehmet possessive here, because that was my next question.