Sound travelling time through multiple mediums
An explosion occurs at the end of a pier. The sound reaches the other end of the pier by traveling through three media: air, fresh water and a slender metal handrail. The speeds of sound in air, water, and the handrail are 343, 1482, and 5040 m/s. The sound travels a distance of 125 m in each medium.
a.) Which medium does the sound arrive first, second and third?
b.) After the first sound arrives, how much later do the second and third sounds arrive?