The speed of sound is given by the formula Speed of sound = square root (Young's Modulus/density) Young's modulus for gold = 78 GPa which is 7.8 * 10^10 Pa Speed of sound = (7.8 * 10^10 / 19.3 ) = sqrt (4.04 * 10^9 ) Speed of sound = 6.36 * 10^4 m/s <<<=== answer.