by how many order of magnitute is the speed of light greater than the average speed of grey sound? Rose Diamond when he set the hight gate track 710 m record of for this 47.43 sec in April 2003

710m/47.43s = close to 15 m/s.
The speed of light is 3 x 10^8 m/s or 30 x 10^7 m/s. That is 30 x 10^7/15 = 20,000,000 give or take a little. That is ABOUT 7 orders of magnitude (count the zeros) faster for the speed of light over the track star. You don't mention how accurately you want this calculated.

thanks