The definiton of period (T) Is T = 1/f ; Therefore if you know that the period is 2.5 microseconds (=2.5 x 10-6) then the frequency is f=1/(2.5x10-6)= 4 x 105 Hz

If you mean a wave that has a frequency of 10 hz at 360 m/s, then the answer is 1/36 of a second. The period is the inverse of the wavelength and the wavelength is equal to the wave speed divided y the frequency. 360/10=36 and the inverse of 36 is 1/36.

The period of a wave of 10 Hz is 1/(10 Hz) = 0.1 seconds. It doesn't matter what speed it's traveling at. (And "moves at 360 ms" is meaningless. You probably mean "360 m/s"?)