The original sentence will found in second answer of this question thread.
Original sentence: 1. Es wird nächsten Sommer/im nächsten Sommer sein.
I have written the sentence below only with Preposition + Article
- Es wird im nächsten Sommer sein.
In the 2nd sentence the determiner im = in + dem(Dativ) and adjective nächsten (accusative) are in two different case before the noun (Sommer),
So my question is: Is it appropriate to have two different case of determiner and adjective before an individual noun which they both modify?