In air, the velocity of sound waves is relatively constant and does not depend on frequency. The speed of sound in dry air at room temperature is approximately 343 meters per second (m/s).
Since the velocity of sound is the same for both waves, the ratio of their velocities would be 1:1. In other words, the two sound waves with frequencies of 300 Hz and 600 Hz would travel at the same speed in air. The difference in their frequencies does not affect the velocity of propagation.