Answer:
Wave X has a shorter wavelength.
Explanation:
The relation between the speed of a wave, its wavelength and frequency is given by :
It can be seen that the relationship between the frequency and wavelength is inverse.
In this problem, it is mentioned that two sound waves (wave X and wave Y) are moving through a medium at the same speed. The frequency of wave X is greater than wave Y. Then it would mean that wave X have shorter wavelength than wave Y (due to inverse relation).