Help help help on speed of sound

[dlre]

Homework Statement

the air temperature is 20 degree celcius. you are swimming underwater when you hear a boat noise. then 305s later, you hear a crash. if the speed of sound in wter is 1450m/s, how long after the crash does your friend on the dock beside oyu hear the crash?

Homework Equations

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The Attempt at a Solution

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[Pengwuino]

Do you know the speed of sound in air?

 

[dlre]

346m/s?

 

[Pengwuino]

Ok so you know the time it takes for the sound to transverse a distance in a certain medium is $$t = \frac{d}{{v_{medium} }}$$. You really don't know the "distance" because it's not actually stated in the problem that the crash occurred immediately after the boat sound is heard but you CAN determine the ratio of the time sound waves take to reach each person using the equation.