For a species with a haploid number of 15 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes?

The answer is:  " 32,768 " .

Explanation:

 →  2ⁿ  = ? ;  {that is: "2" , raised to the "n th" power, equals {what value} ?

 → Note that "n" is the haploid number, which is: 
                           "15" (value given within this very question).

→ So we plug in "15" for "n" ; to obtain the "final value" —
                                                          which is the answer.

           →  As such:  " 2¹⁵ = 32,768 " .  (using scientific calculator online).

           →  The answer is:  " 32,768 " .